title: Molecular morphology and function of bull spermatozoa linked to histones and associated with fertility.
abstract: Sub-par fertility in bulls is influenced by alterations in sperm chromatin, and it might not be solved with increased sperm concentration in artificial insemination. Appropriate histone retention during sperm chromatin condensation plays critical roles in male fertility. The objective of this study was to determine failures of sperm chromatin condensation associated with abnormal persistence or accessibility of histones by aniline blue (ANBL) test, expression levels, and cellular localizations of one variant and two core histones (H3.3, H2B, and H4 respectively) in the spermatozoa of low-fertility (LF) vs high-fertility (HF) bulls. The expression levels and cellular localizations of histones in spermatozoa were studied using immunoblotting, immunocytochemistry, and staining methods. The bioinformatics focused on the sequence identity and evolutionary distance of these proteins among three mammalian species: bovine, mouse, and human. We demonstrated that ANBL staining was different within the LF (1.73 (0.55, 0.19)) and HF (0.67 (0.17, 0.06)) groups (P<0.0001), which was also negatively correlated with in vivo bull fertility (r=-0.90, P<0.0001). Although these histones were consistently detectable and specifically localized in bull sperm cells, they were not different between the two groups. Except H2B variants, H3.3 and H4 showed 100% identity and were evolutionarily conserved in bulls, mice and humans. The H2B variants were more conserved between bulls and humans, than in mice. In conclusion, we showed that H2B, H3.3, and H4 were detectable in bull spermatozoa and that sperm chromatin condensation status, changed by histone retention, is related to bull fertility.
authors.affiliation: Functional Genomics of Animal Reproduction and Development, Department of Animal and Dairy Sciences, Mississippi State University, 4025 Wise Center, Mississippi State, Mississippi 39762, USA.
authors.forename: Rodrigo V
authors.initials: RV
authors.lastname: de Oliveira
authors.forename: Sule
authors.initials: S
authors.lastname: Dogan
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Belser
authors.forename: Abdullah
authors.initials: A
authors.lastname: Kaya
authors.forename: Einko
authors.initials: E
authors.lastname: Topper
authors.forename: Arlindo
authors.initials: A
authors.lastname: Moura
authors.forename: Giselle
authors.initials: G
authors.lastname: Thibaudeau
authors.forename: Erdogan
authors.initials: E
authors.lastname: Memili
mesh_terms: D000814:Aniline Compounds; D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D002843:Chromatin / Q000378:metabolism / Q000502:physiology*; D005298:Fertility / Q000502:physiology*; D006657:Histones / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D017386:Sequence Homology, Amino Acid; D013094:Spermatozoa / Q000166:cytology* / Q000502:physiology*
chemical_list: D000814:Aniline Compounds; D002843:Chromatin; D006657:Histones; C017006:aniline blue