Anne Hege Alm-Kristiansen

• Shrestha, Asmita; van_Son, Maren; Hashim, Adnan; Rouzbehani, Soudabeh; Gilfillan, Gregor & Berge, Urszula [Show all 8 contributors for this article] (2026). Sperm RNA landscape during sexual maturation in Duroc boars. BMC Genomics. 27(1). doi: 10.1186/s12864-025-12490-0. Full text in Research Archive Show summary

  Background Sexual maturation in boars impacts reproductive efficiency in swine production, yet the molecular mechanisms underlying this developmental transition remain poorly understood. This study aimed to investigate the transcriptomic changes in sperm from Duroc boars during sexual maturation, conducting a longitudinal analysis. The total RNA and miRNA profiles from the same individuals (n = 6) at puberty (7.24 ± 0.39 months) and sexual maturity (10 ± 0.40 months) were compared, identifying molecular signatures associated with reproductive development. Total RNA sequencing (Illumina NovaSeq-6000) and miRNA sequencing (Illumina NextSeq-500) were performed on all 12 paired samples (6 boars at 2 time points), followed by differential expression analysis using a paired statistical model in DESeq2 to account for repeated measures. Results Differential expression analysis identified 60 differentially expressed genes using stringent criteria (adj P < 0.05, |log2FC| ≥ 0.5), with 65% upregulated in sperm of boars 10-months versus 7-months of age. Key upregulated genes included NCLN, RGS12, CIB2, FOXP4, PHC1, CDC25B and AKAP1, while HSP90AA1, EVI5, FSIP2, VDAC3, and ALMS1 were key downregulated genes. Furthermore, Gene ontology analysis revealed significant enrichment of 11 biological processes, mostly related to reproductive development, and four molecular functions (transferase activity, transferring phosphorus-containing groups, protein serine/threonine kinase activity, protein kinase activity and signal sequence binding). Additionally, our miRNA analysis identified six differentially abundant miRNAs (adj P < 0.05 & |log2FC| ≥ 0.5); ssc-miR-193a-5p, ssc-miR-574-3p, ssc-miR-126-3p, ssc-miR-196a, ssc-miR-210 were upregulated, and ssc-miR-338 showed downregulation in 10-months age. Integrated analysis of differentially expressed mRNA and predicted miRNA targets identified 18 miRNA-mRNA regulatory pairs, enriched in pathways related to cell cycle processes and chromatin binding, suggesting coordinated regulation across RNA biotypes in sperm during sexual maturation. Conclusions Our study reveals coordinated transcriptomic shifts in boar sperm during sexual maturation. Most genes show increased RNA abundance at 10 months of age, with enrichment in terms of reproductive development. Several miRNAs appear to regulate these changes through targeted mRNA interactions. These findings expand our understanding of the biological processes underlying sexual maturation in pigs.

• Rouzbehani, Soudabeh; Shrestha, Asmita; Haque, Nazia; Nushrat, Syeda Afsana; Zeremichael, Teklu Tewoldebrhan & Nordborg, Anna [Show all 8 contributors for this article] (2025). Influence of sexual maturity on sperm quality in Duroc boars. Animal Reproduction Science. ISSN 0378-4320. 284. doi: 10.1016/j.anireprosci.2025.108053. Full text in Research Archive Show summary

  The objective of this study was to evaluate sperm quality of Duroc boars during sexual maturation and examine whether these parameters were related to metabolites in semen. Ejaculates were collected longitudinally from 28 Duroc boars at approximately 7 months of age (Age 1), 6 weeks later (Age 2) and 12 weeks later (Age 3). Motility characteristics, acrosome integrity, and viability were assessed on collection day and after five days storage at 18°C using computer-assisted sperm analysis and flow cytometry, while DNA fragmentation was measured on day five. Amino acid and amine concentrations in semen were measured by liquid chromatography-mass spectrometry and correlated with sperm quality parameters. Motility, rapid progressive motility, and acrosome intact live sperm increased significantly (adj P < 0.05) with boar maturation. Mature boars (Age 2 and Age 3) maintained superior sperm quality compared to younger boars after storage. The DNA fragmentation index was low in all samples but declined significantly from 1 % at Age 1 to 0.64 % at Age 3 (adj P < 0.05). Correlation analysis showed significant relationships between sperm quality and specific metabolites. Cystine, glutamate, aspartate, choline and taurine were inversely correlated with progressive and rapid progressive motility, while showing positive correlation with rapid non-progressive motility. These findings demonstrate that sperm quality continues improving beyond initial reproductive ability, especially between Age 1 and Age 3, with improvements in motility, viability, chromatin stability, and storage resilience. The observed relationships between metabolites and sperm quality parameters provide insights into biochemical mechanisms underlying sperm functionality during sexual maturation.

• Shrestha, Asmita; Gaustad, Ann Helen; Øiaas, Janne Beate; Nordborg, Anna; Kommisrud, Elisabeth & van_Son, Maren [Show all 8 contributors for this article] (2025). Untargeted metabolomics reveals changes in boar sperm and seminal plasma metabolites associated with sexual maturity. Journal of Animal Science and Biotechnology. ISSN 1674-9782. 16. doi: 10.1186/s40104-025-01258-x. Full text in Research Archive Show summary

  Background: Boars undergo physiological and biochemical changes in semen composition as they grow from puberty to sexual maturity. However, comprehensive metabolomic profiles of boar semen remain uncharacterised. Understanding metabolic alterations in semen during this period is important for optimising reproductive performance in breeding programs. The aim of this study was to characterise the semen metabolome as boars mature, utilising an untargeted metabolomic approach. Semen samples were collected from 15 Duroc boars at three developmental ages: ~ 7 months, 8.5 months, and 10 months. Sperm and seminal plasma were separated and analysed by hydrophilic interaction and reversed-phase liquid chromatography coupled with mass spectrometry to capture a wide range of metabolites. Results: We identified a total of 4,491 features in boar semen, annotating 92 distinct metabolites. Amino acids, peptides and analogues constituted the most abundant components, followed by fatty acid esters. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) showed a clear separation between metabolomic profiles by age groups. PERMANOVA analysis of PCA scores confirmed statistically significant differences ( P  < 0.05) between younger (7 months) and more mature boars (8.5 months and 10 months). Pathway analysis identified porphyrin metabolism, taurine and hypotaurine metabolism, and glycerolipid metabolism as significantly enriched pathways in sperm, while glutathione and nitrogen metabolism were prominently enriched in seminal plasma. Using linear modelling, partial Spearman correlation and random forest analyses, we identified homoisovanillic acid as a key metabolite discriminating age groups in both sperm and seminal plasma. Additionally, L-glutamic acid, decanoyl-L-carnitine and N-(1,3-Thiazol-2-yl)benzenesulfonamide emerged as important sperm metabolites, while glyceric acid, myo-inositol, glycerophosphocholine, and several other compounds were identified as critical seminal plasma metabolites. Conclusion: This study provides a detailed characterisation of metabolic changes in Duroc boar semen during the transition from puberty to sexual maturity. Our findings enhance the understanding of reproductive development and could inform strategies to assess sexual maturity in breeding programs.

• Shrestha, Asmita; Gaustad, Ann Helen; Øiaas, Janne Beate; Kommisrud, Elisabeth; Son, Maren van & Nordborg, Anna [Show all 7 contributors for this article] (2025). A metabolomic study uncovering key amino acids and amines in Duroc boar semen as biomarkers of sexual maturity. Animal Reproduction Science. ISSN 0378-4320. 275, p. 1–14. doi: 10.1016/j.anireprosci.2025.107800. Full text in Research Archive Show summary

  Metabolomic analysis of boar semen associated with sexual maturation is essential for improving fertility management and breeding, with amino acids and amines playing key roles in the reproductive process. This study aimed to explore changes in amino acids and amines in boar spermatozoa and seminal plasma during puberty to sexual maturity and identify potential biomarkers of sexual maturity. Semen was collected from the same 15 Duroc boars over time at approximately 7 months (Age 1), 8.5 months (Age 2), and 10 months (Age 3). Liquid chromatography-mass spectrometry was used to analyse amino acids and amines in spermatozoa and seminal plasma separately. Multivariate analysis (PLS-DA) revealed pronounced age- dependent changes in amino acids and amines in spermatozoa between Age 1 and Age 3, and more subtle shifts in seminal plasma. Univariate analysis (Repeated measure ANOVA/Friedman) revealed that glutamate and taurine had significant pairwise differences in seminal plasma (P < 0.05). In sperm, 15 amino acids (glutamate, alanine, aspartate, choline, taurine, histidine, methionine, tryptophan, leucine, cystine, tyrosine, arginine, lysine, valine and glycine) exhibited significant pairwise differences (P < 0.05). VIP scoring (>1.5) prioritised glutamate, alanine, aspartate, and choline as key contributors to the variations and pathway analysis implicated alanine, aspartate and glutamate metabolism, and histidine metabolism linked to sexual maturity. Our study highlights metabolic changes during sexual maturation, identifying potential biomarkers for assessing reproductive maturity. These findings are initial steps toward optimising younger boars’ usage in breeding, enhancing genetic gain, and reducing costs associated with their non-productive days at AI centres.

• Haug, Linda Marijke Dekker; Wilson, Robert Charles & Alm-Kristiansen, Anne Hege (2024). Epigenetic-related transcriptional reprogramming elucidated by identification and validation of a novel reference gene combination for RT-qPCR studies in porcine oocytes of contrasting quality. Molecular Biology Reports. ISSN 0301-4851. 51(1). doi: 10.1007/s11033-024-09319-6. Full text in Research Archive Show summary

  Background Reliable RT-qPCR results are dependent on appropriate normalisation. Oocyte maturation studies can be challenging in this respect, as the stage of development can distinctively affect reference gene transcript abundance. The aim of this study was to validate the use of reference genes in oocyte in vitro maturation RT-qPCR studies, and thereafter, examine the abundance of transcripts supporting histone modification during oocyte and early embryo development in oocytes of contrasting quality. Methods and results Total RNA from oocytes from prepubertal gilts and sows was extracted either directly succeeding follicle aspiration or after 44 h in vitro maturation, followed by RT-qPCR. The stability of YWHAG, HPRT1, ACTB, GAPDH, HMBS and PFKP, was analysed by NormFinder and further cross-validated by assessing results generated following application of different combinations of potential reference genes for normalisation of the RT-qPCR data. Combining ACTB and PFKP generated high stability according to NormFinder and concordant results. Applying this normalisation, gilt derived oocytes displayed significantly higher abundance than oocytes from sows of almost all the epigenetic-related transcripts studied (HDAC2, SIRT1, SALL4, KDM1A, KDM1B, KDM5A), both before and after maturation. Conclusions This study identified the combined use of ACTB and PFKP as the optimal normalisation for porcine oocyte RT-qPCR data. In oocytes collected from prepubertal gilts, transcription did not appear to be silenced at the time of aspiration, and accumulation of transcripts supporting histone modification facilitating proper fertilization and further embryo development seemed delayed. The results imply the epigenetic-related transcripts may have potential as markers of oocyte quality.

• Haug, Linda Marijke Dekker; Jochems, Reina; Gaustad, Ann Helen; Kommisrud, Elisabeth; Myromslien, Frøydis Deinboll & Grindflek, Eli [Show all 7 contributors for this article] (2023). Liquid storage of porcine in vitro -produced blastocysts; a practical approach for short storage. Zygote (Cambridge. Print). ISSN 0967-1994. 31(5), p. 441–450. doi: 10.1017/S0967199423000308. Full text in Research Archive
• Alm-Kristiansen, Anne Hege (2023). Motility Subpopulations with Distinct Motility Characteristics Using Swim-Up-Selected Sperm Cells from Norwegian Red Bulls: Effects of Freezing–Thawing and Between-Bull Variation. Biology (Basel). 12(8). doi: 10.3390/biology12081086. Full text in Research Archive Show summary

  Discrete subpopulations of motile sperm cells have been found for several species and are implicated to be important for sperm functionality. The aim of this present study was to examine the motile subpopulations in swim-up-selected bull spermatozoa and the relationship between subpopulations in fresh and frozen–thawed sperm cells. In experiment 1, swim-up (SWUP)-selected and non-selected (control) sperm cells were analyzed using a Computer-Assisted Sperm Analyzer (CASA). In experiment 2, the semen from nine bulls was cryopreserved and analyzed using CASA both before and after freezing and after incubation at physiological temperatures. The SWUP population had a higher proportion of total motility, progressivity, and velocity compared to the control (p < 0.05). Likewise, both incubation over time and cryopreservation affected motility and motility parameters (p < 0.05). The population of rapid progressive (RapidP) sperm cells dominated the SWUP fraction and was higher than in the control samples (p < 0.05). Furthermore, RapidP was also the main part of fresh semen, but decreased significantly over time during incubation and due to cryopreservation. In conclusion, RapidP was the main population in SWUP-selected spermatozoa and seems to be an important subpopulation contributing to the differences between treatments and in response to the freezing of sperm cells.

• Haug, Linda Marijke Dekker; Wilson, Robert Charles; Gaustad, Ann Helen; Jochems, Reina; Kommisrud, Elisabeth & Grindflek, Eli [Show all 7 contributors for this article] (2023). Cumulus Cell and Oocyte Gene Expression in Prepubertal Gilts and Sows Identifies Cumulus Cells as a Prime Informative Parameter of Oocyte Quality. Biology (Basel). 12(12). doi: 10.3390/biology12121484. Full text in Research Archive Show summary

  Cumulus cells (CCs) are pivotal during oocyte development. This study aimed to identify novel marker genes for porcine oocyte quality by examining the expression of selected genes in CCs and oocytes, employing the model of oocytes from prepubertal animals being of reduced quality compared to those from adult animals. Total RNA was extracted either directly after follicle aspiration or after in vitro maturation, followed by RT-qPCR. Immature gilt CCs accumulated BBOX1 transcripts, involved in L-carnitine biosynthesis, to a 14.8-fold higher level (p < 0.05) relative to sows, while for CPT2, participating in fatty acid oxidation, the level was 0.48 (p < 0.05). While showing no differences between gilt and sow CCs after maturation, CPT2 and BBOX1 levels in oocytes were higher in gilts at both time points. The apparent delayed lipid metabolism and reduced accumulation of ALDOA and G6PD transcripts in gilt CCs after maturation, implying downregulation of glycolysis and the pentose phosphate pathway, suggest gilt cumulus–oocyte complexes have inadequate ATP stores and oxidative stress balance compared to sows at the end of maturation. Reduced expression of BBOX1 and higher expression of CPT2 in CCs before maturation and higher expression of G6PD and ALDOA after maturation are new potential markers of oocyte quality.

• Berg, Halldor Felde; Heringstad, Bjørg; Alm-Kristiansen, Anne Hege; Kvale, Vilde Granne; Dragset, Knut Ingolf & Waldmann, Andres [Show all 8 contributors for this article] (2020). Ovarian Follicular Response to Oestrous Synchronisation and Induction of Ovulation in Norwegian Red Cattle. Acta Veterinaria Scandinavica (AVS). ISSN 0044-605X. 62. doi: 10.1186/s13028-020-00514-6. Full text in Research Archive Show summary

  Oestrous synchronisation of cattle has been widely applied to accomplish simultaneous ovulation in animals and facilitate timed artificial insemination. The main aim of this study was to investigate the ovarian follicular growth and ovulatory response to oestrus and ovulation synchronisation in Norwegian Red heifers and cows. Oestrous cycles in 34 heifers and 10 cows from 4 herds were synchronised with two PGF2α analogue treatments 11 days apart, followed by GnRH analogue treatment for induction of ovulation. Thereafter, the ovaries were examined by ultrasonography at 3 h intervals until ovulation. Results The luteolytic effect of the PGF2α analogue was verified in 9 of 10 cows by progesterone contents in milk. Maximum physical activity of the cows occurred on average 69 h after PGF2α analogue treatment. An ovulatory response was recorded in 95.5% (42/44) of the animals. A significant difference in follicle size at ovulation was found between 2 of the herds. Animals with medium sized and large follicles and heifers aged > 16 months ovulated earlier than other animals. Conclusions The applied sequence of treatments in the study was shown to be effective in synchronizing and inducing ovulation within a relatively narrow time interval in the Norwegian Red heifers and cows, consistent with findings in other cattle breeds.

• Berg, Halldor Felde; Spång, Heidi Cecilie Larsen; Heringstad, Bjørg; Ropstad, Erik; Alm-Kristiansen, Anne Hege & Kommisrud, Elisabeth (2020). Studies of gel with immobilized semen by intrauterine endoscopy post-artificial insemination. Reproduction in domestic animals (1990). ISSN 0936-6768. 55(3), p. 401–404. doi: 10.1111/rda.13630. Full text in Research Archive
• Berg, Halldor Felde; Kommisrud, Elisabeth; Bai, Godlove; Gaustad, Eline Rustad; Klinkenberg, Geir & Standerholen, Fride Berg [Show all 11 contributors for this article] (2018). Comparison of sperm adenosine triphosphate content, motility and fertility of immobilized and conventionally cryopreserved Norwegian Red bull semen. Theriogenology. ISSN 0093-691X. 121, p. 181–187. doi: 10.1016/j.theriogenology.2018.08.016. Full text in Research Archive
• Alm-Kristiansen, Anne Hege; Standerholen, Fride Berg; Bai, Godlove; Waterhouse, Karin Elisabeth & Kommisrud, Elisabeth (2018). Relationship between post-thaw adenosine triphosphate content, motility and viability in cryopreserved bovine semen applying two different preservation methods. Reproduction in domestic animals (1990). ISSN 0936-6768. p. 1–8. doi: 10.1111/rda.13285. Full text in Research Archive
• Alm-Kristiansen, Anne Hege; Gaustad, Eline Rustad; Bai, Guoyun; Standerholen, Fride Berg; Klinkenberg, Geir & Kommisrud, Elisabeth [Show all 7 contributors for this article] (2018). In vitro studies of Norwegian Red bovine semen immobilized and cryopreserved in alginate solid gel network. Reproduction in domestic animals (1990). ISSN 0936-6768. 53(2), p. 365–370. doi: 10.1111/rda.13115. Full text in Research Archive
• Alm-Kristiansen, Anne Hege; Dalen, Gunnar; Klinkenberg, Geir; Bekk, Laila; Thorkildsen, Lill Therese & Waterhouse, Karin Elisabeth [Show all 7 contributors for this article] (2017). Reproductive performance of immobilized cryopreserved bovine semen used for timed artificial insemination. Reproduction in domestic animals (1990). ISSN 0936-6768. 52(6), p. 1019–1024. doi: 10.1111/rda.13017. Full text in Research Archive
• Alm-Kristiansen, Anne Hege; Lorenzo, Petra Isabel O.; Molværsmyr, Ann-Kristin; Matre, Vilborg; Ledsaak, Marit & Sæther, Thomas [Show all 7 contributors for this article] (2011). PIAS1 interacts with FLASH and enhances its co-activation of c-Myb. Molecular Cancer. 10. doi: 10.1186/1476-4598-10-21. Full text in Research Archive Show summary

  Background FLASH is a huge nuclear protein involved in various cellular functions such as apoptosis signalling, NF-κB activation, S-phase regulation, processing of histone pre-mRNAs, and co-regulation of transcription. Recently, we identified FLASH as a co-activator of the transcription factor c-Myb and found FLASH to be tightly associated with active transcription foci. As a huge multifunctional protein, FLASH is expected to have many interaction partners, some which may shed light on its function as a transcriptional regulator. Results To find additional FLASH-associated proteins, we performed a yeast two-hybrid (Y2H) screening with FLASH as bait and identified the SUMO E3 ligase PIAS1 as an interaction partner. The association appears to involve two distinct interaction surfaces in FLASH. We verified the interaction by Y2H-mating, GST pulldowns, co-IP and ChIP. FLASH and PIAS1 were found to co-localize in nuclear speckles. Functional assays revealed that PIAS1 enhances the intrinsic transcriptional activity of FLASH in a RING finger-dependent manner. Furthermore, PIAS1 also augments the specific activity of c-Myb, and cooperates with FLASH to further co-activate c-Myb. The three proteins, FLASH, PIAS1, and c-Myb, are all co-localized with active RNA polymerase II foci, resembling transcription factories. Conclusions We conclude that PIAS1 is a common partner for two cancer-related nuclear factors, c-Myb and FLASH. Our results point to a functional cooperation between FLASH and PIAS1 in the enhancement of c-Myb activity in active nuclear foci.

• Sæther, Thomas; Pattabiraman, D.R.; Alm-Kristiansen, Anne Hege; Kielland, Linn Troye Vogt-; Gonda, T.J. & Gabrielsen, Odd Stokke (2011). A functional SUMO-interacting motif in the transactivation domain of c-Myb regulates its myeloid transforming ability. Oncogene. ISSN 0950-9232. 30(2), p. 212–222. doi: 10.1038/onc.2010.397. Full text in Research Archive
• Alm-Kristiansen, Anne Hege; Norman, IL; Matre, Vilborg & Gabrielsen, Odd Stokke (2009). SUMO modification regulates the transcriptional activity of FLASH. Biochemical and Biophysical Research Communications - BBRC. ISSN 0006-291X. 387(3), p. 494–499. doi: 10.1016/j.bbrc.2009.07.053. Full text in Research Archive
• Matre, Vilborg; Nordgård, Oddmund; Alm-Kristiansen, Anne Hege; Ledsaak, Marit & Gabrielsen, Odd Stokke (2009). HIPK1 interacts with c-Myb and modulates its activity through phosphorylation. Biochemical and Biophysical Research Communications - BBRC. ISSN 0006-291X. 388(1), p. 150–154. doi: 10.1016/j.bbrc.2009.07.139. Full text in Research Archive
• Alm-Kristiansen, Anne Hege; Sæther, Thomas; Matre, Vilborg; Otnæss, Siv Kolstø; Dahle, Øyvind & Gabrielsen, Odd Stokke (2008). FLASH acts as a co-activator of the transcription factor c-Myb and localizes to active RNA polymerase II foci. Oncogene. ISSN 0950-9232. 27, p. 4644–4656. doi: 10.1038/onc.2008.105. Full text in Research Archive
• Sæther, Thomas; Berge, T; Ledsaak, Marit; Matre, Vilborg; Alm-Kristiansen, Anne Hege & Dahle, O [Show all 8 contributors for this article] (2007). The chromatin remodeling factor Mi-2 alpha acts as a novel co-activator for human c-Myb. Journal of Biological Chemistry. ISSN 0021-9258. 282. doi: 10.1074/jbc.M700755200. Full text in Research Archive

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• Shrestha, Asmita; Nordborg, Anna; Gaustad, Ann Helen; Kommisrud, Elisabeth; Son, Maren van & Alm-Kristiansen, Anne Hege (2024). Investigation of Biomarkers of Sexual Maturity in Boars using Targeted Metabolomics. Full text in Research Archive
• Alm-Kristiansen, Anne Hege (2023). Can sperm motility subpopulation analysis enhance the productivity in animal breeding? Full text in Research Archive
• Shrestha, Asmita & Alm-Kristiansen, Anne Hege (2023). Exploring RNA as biomarker of fertility in boars. Full text in Research Archive
• Haug, Linda Marijke Dekker; Wilson, Robert Charles; Gaustad, Ann Helen; Jochems, Reina; Kommisrud, Elisabeth & Grindflek, Eli [Show all 7 contributors for this article] (2023). Cumulus cell gene expression identifies key mechanisms influencing porcine oocyte developmental competence. Full text in Research Archive
• Haug, Linda Marijke Dekker; Wilson, Robert Charles; Gaustad, Ann Helen; Jochems, Reina; Kommisrud, Elisabeth & Grindflek, Eli [Show all 7 contributors for this article] (2023). Cumulus cell gene expression identifies key mechanisms influencing porcine oocyte developmental competence. Full text in Research Archive
• Alm-Kristiansen, Anne Hege (2022). Successful spermatozoa? Flow cytometry analysis of different animal species. Full text in Research Archive
• Berg, Fride; Alm-Kristiansen, Anne Hege; Waterhouse, Karin E; Myromslien, Frøydis Deinboll; Klinkenberg, Geir & Kommisrud, Elisabeth (2015). Prolonging the shelf-life of spermatozoa by immobilizing technology. Full text in Research Archive
• Kommisrud, Elisabeth; Klinkenberg, Geir; Bekk, Laila & Alm-Kristiansen, Anne Hege (2014). Prolonging shelf life of spermatozoa by immobilizing technology. Full text in Research Archive
• Molværsmyr, Ann-Kristin; Ledsaak, Marit; Alm-Kristiansen, Anne Hege; Lorenzo, Petra Isabel O.; Matre, Vilborg & Sæther, Thomas [Show all 7 contributors for this article] (2012). The SUMO E3 ligase PIAS1 interacts with c-Myb and enhances its transcriptional activity. Full text in Research Archive Show summary

  PIAS1 belongs to the family of Protein Inhibitor of Activated STAT. In addition to their function as negative regulators of STAT signaling, PIAS proteins also act as SUMO E3 ligases, enhancing sumoylation of target proteins. This activity is dependent on a RING finger domain present in PIAS proteins. Even though sumoylation of trancriptional regulators often leads to inhibition of their activity, PIAS proteins are known to act as both negative and positive regulators of transcription, in both SUMO-dependent or independent manners. We have previously identified FLASH (FLICE associated huge protein) as a co-activator of the transcription factor c-Myb. To find additional FLASH-associated proteins, we performed a yeast two-hybrid screening with FLASH as bait, and identified the SUMO E3 ligase PIAS1 as an interacting partner. Functional assays revealed that PIAS1 enhances FLASH's activity and its ability to co-activate c-Myb in a RING finger-dependent manner. The three proteins, FLASH, PIAS1, and c-Myb, are all co-localized with active RNA polymerase II foci. As an E3 ligase we expect PIAS1 to sumoylate c-Myb and inhibit the transcriptional activity of c-Myb. Contrarily, we only see weak sumoylation of c-Myb and an enhancement of c-Myb transactivation. We are currently studying the involvement of p300 in the PIAS1 enhancement of c-Myb transcriptional activity. We suggest that the RING finger domain of PIAS1 have two functions, one being a SUMO E3 ligase and another recruiting the co-activator p300.

• Sæther, Thomas; Bengtsen, Mads; Molværsmyr, Ann-Kristin; Pattabiraman, D.R.; Alm-Kristiansen, Anne Hege & Ledsaak, Marit [Show all 8 contributors for this article] (2012). Regulating the regulator: SUMO functions as a master switch for the transcription factor c-Myb. Full text in Research Archive Show summary

  The oncoprotein c-Myb is an essential hematopoietic transcription factor that controls proliferation and differentiation of progenitors during blood cell development. This transcriptional activator plays a direct role in lineage fate selection, cell cycle progression, and differentiation of myeloid as well as B- and T-lymphoid progenitors. Recent studies have shown that c-Myb accomplishes this by controlling the expression of several important hematopoietic transcriptions factors, and in that way acts as a master regulator. c-Myb is modified by SUMO on two lysines in its C-terminal regulatory domain (CRD), and is able to bind SUMO via a SUMO-interacting motif (SIM) in the central transactivation domain. Both these SUMO-contacts are important in regulating the transactivation activity of c-Myb, and breaking these contacts makes c-Myb super active. We have found that the ability of c-Myb to synergize with other transcription factors on compound promoters is restricted by synergy control, linked to the SUMOylation of CRD. De-SUMOylation of c-Myb leads to a dramatic change in synergy behavior, which correlates with a SUMO-dependent differential recruitment of p300 and a corresponding local change in histone H3 and H4 acetylation. Using cell-based transformation assays, we have addressed the abilities of c-Myb SUMO binding and conjugation mutants to transform hematopoietic cells. Interestingly, only loss of SUMO binding, and not SUMO conjugation, enhances the myeloid transformational potential of c-Myb. c-Myb with the SIM mutated confers a high proliferative ability and causes an effective differentiation block. This establishes SUMO binding as a mechanism responsible for keeping the transforming potential of the oncoprotein in check. Taken together this implies that SUMO functions as a master regulatory switch for c-Myb. Given that the SUMO-system may be perturbed in different cancers, c-Myb may be particularly vulnerable to such changes and thus mediate dramatic downstream effects.

• Krogens, A; Alm-Kristiansen, Anne Hege & Waterhouse, Karin E. (2012). Quality of cryopreserved bull spermatozoa selected by swim-up and Percoll procedures at two different temperatures. Reproduction in domestic animals (1990). ISSN 0936-6768. 47(Supp. 5), p. 92–93. Full text in Research Archive
• Sæther, Thomas; Molværsmyr, Ann-Kristin; Gilfillan, Siv; Alm-Kristiansen, Anne Hege; Aabel, Linn Ingeborg & Matre, Vilborg [Show all 7 contributors for this article] (2011). The hematopoietic transcription factor c-Myb functions as an epigenetic organizer. Full text in Research Archive Show summary

  The c-Myb protein belongs to a group of early hematopoietic transcription factors that are important for progenitor generation and proliferation. These factors have been hypothesized to participate in establishing epigenetic patterns specific for hematopoietic genes. Consistent with its role as a regulator of stem and progenitor cells, a picture is now emerging where c-Myb appears to be directly involved in chromatin modulation. Several lines of evidence, both from our lab and others, point to a particular involvement of c-Myb in histone interaction and chromatin modification. Importantly, the DNA-binding domain of c-Myb not only binds DNA. Its SANT properties also enables it to bind to the N-terminal tail of histone H3 and facilitates histone acetylation by p300. We show that SUMOylation of c-Myb causes differential recruitment of p300 to chromatin leading to a local change in histone H3 and H4 acetylation, supporting the hypothesis of SUMO as a determinant of chromatin signatures. p300/CBP was the first chromatin modifying enzyme demonstrated to be recruited to regulatory gene elements by c-Myb. Today the catalogue also includes MLL, PIAS1, HIPK1, and Mi-2, all of which have enzymatic activity. Together with FLASH and PIAS1, c-Myb also co-localizes with active RNA polymerase II foci, resembling transcription factories. The aim of the present work in to define a specific Myb-induced epigenetic signature by correlating the recruitment of these co-factors with histone marks on Myb-regulated genomic elements.

• Sæther, Thomas; Berge, Tone; Ledsaak, Marit; Matre, Vilborg; Alm-Kristiansen, Anne Hege & Dahle, Øyvind [Show all 8 contributors for this article] (2007). The chromatin remodelling factor Mi-2alpha acts as a novel co-activator for human c-Myb. Full text in Research Archive Show summary

  The c-Myb protein belongs to a group of early hematopoietic transcription factors that are important for progenitor generation and proliferation. These factors have been hypothesized to participate in establishing chromatin patterns specific for hematopoietic genes. In a two-hybrid screening we identified the chromatin remodelling factor Mi-2alpha as an interaction partner for human c-Myb. The main interacting domains were mapped to the N-terminal region of Mi-2alpha and the DNA-binding domain of c-Myb. Surprisingly, functional analysis revealed that Mi-2alpha previously studied as a subunit in the NuRD co-repressor complex, enhanced c-Myb dependent reporter activation. Consistently, knock-down of endogenous Mi-2alpha in c-Myb expressing K562 cells led to down-regulation of the c-Myb target genes NMU and ADA. When wild-type and helicase-dead Mi-2alpha were compared, the Myb-Mi-2alpha co-activation appeared to be independent of the ATPase/DNA helicase activity of Mi-2alpha. The rationale for the unexpected co-activator function seems to lie in a dual function of Mi-2alpha, by which this factor is able to repress transcription in a helicase-dependent and activate in a helicase-independent fashion, as revealed by Gal4 tethering experiments. Interestingly, desumoylation of c-Myb potentiated the Myb-Mi-2alpha transactivational co-operation, as did cotransfection with p300.

• Alm-Kristiansen, Anne Hege; Sæther, Thomas; Ledsaak, Marit; Matre, Vilborg & Gabrielsen, Odd Stokke (2006). FLASH is a coregulator of the transcription factor c-Myb. Full text in Research Archive
• Shrestha, Asmita; Alm-Kristiansen, Anne Hege; Kommisrud, Elisabeth & Son, Maren van (2025). Metabolomics, transcriptomics, and sperm quality analyses to investigate biomarkers in boar semen related to sexual maturity. Universitet i Innlandet / University of Inland Norway. ISSN 9788283805772. Full text in Research Archive Show summary

  Puberty to sexual maturity marks a key transition in boar reproductive development, yet the molecular and functional changes that occur in semen during this transition remain poorly described. In modern pig breeding, artificial insemination is central to breeding and genetic improvement, and the ability to use boars as young as possible can reduce costs and accelerate genetic gains. At present, decisions about when the boars are ready for semen collection rely mainly on age and analysis of ejaculate volume, sperm concentration, motility, and morphology, which do not fully capture the biological processes underlying maturation. This thesis addresses these gaps by following Duroc boars longitudinally from puberty to sexual maturity, with metabolomics, transcriptomics, and sperm quality assessments to uncover the molecular and functional signatures of maturation. Semen samples were collected longitudinally from individual boars through three maturation ages: at approximately 7 months, 6 weeks later, and finally 12 weeks after the initial sample collection. This longitudinal approach eliminated inter-individual genetic variability while capturing the genuine maturational period. Across four studies, complementary approaches were applied to investigate different biological layers, including targeted metabolomics, untargeted metabolomics, sperm functional assessment, and transcriptomic profiling. Targeted metabolomics was used to quantify amino acids and amines in sperm and seminal plasma, identifying glutamate, alanine, aspartate, choline, and taurine in sperm as key metabolites that changed significantly with age and may serve as potential biomarkers of sexual maturity. Untargeted metabolomics expanded this analysis, capturing thousands of features and highlighting pathways such as porphyrin metabolism, taurine and hypotaurine metabolism, and glycerolipid metabolism, which were significantly enriched during sexual maturation. Functional analyses showed that sperm motility, acrosome integrity and viability, DNA integrity, and tolerance to semen storage all improved significantly as boars matured. Several metabolites, including glutamate, cystine, aspartate, taurine, and choline, were linked directly to these functional gains. Transcriptomic profiling of sperm revealed dynamic changes in both coding and non-coding RNAs. A total of 60 genes and six miRNAs were identified as differentially expressed, which are associated with key reproductive processes such as spermatogenesis and germ cell development. This provides insights into the molecular mechanisms that drive functional improvements. Furthermore, an integrated mRNA-miRNA analysis identified regulatory networks that could influence the maturation process. Together, these findings provide the first comprehensive longitudinal characterization of sexual maturation in boars. This thesis contributes both to fundamental knowledge and applied value to the field of animal reproduction. From a practical perspective, it establishes a basis for further research to develop molecular biomarkers that can guide the usage of young boars in semen production and breeding, thereby reducing non-productive days and accelerating genetic gain in breeding programs.

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