Proteomic and genetic dissection of Testis specific Histone 2B in infertile men reveals its contribution to meiosis and sperm motility.

Investigate Testis specific Histone 2B (TSH2B) and its gene anomalies in infertile men DESIGN: Case- control study SUBJECTS: Fertile and infertile men INTERVENTION: Not applicable MAIN OUTCOME MEASURES: Histone and protamine status of sperm was studied by Aniline blue and Chromomycin A3 (CMA3) staining, respectively. TSH2B, total H2B and phosphorylated TSH2B (pTSH2B) were estimated by Western blot analysis. The frequency of genetic polymorphisms/ rare variants in H2BC1 was studied by Sanger sequencing. Phosphosites on TSH2B in sperm were identified by RP-HPLC purification of TSH2B followed by mass spectrometric analysis.Aniline blue and CMA3 staining of sperm revealed significantly higher histone retention and low protamine in sperm of infertile men. Sperm TSH2B and total H2B levels were significantly lower in oligozoospermic and oligoasthenozoospermic men (p < 0.001 for TSH2B & total H2B in both groups). TSH2B levels were comparable in asthenozoospermic men, however, pTSH2B was significantly low (p < 0.05). H2BC1 gene sequencing identified 6 variants, of which, two are rare variants (rs368672899 and rs544942090) and 4 (rs4711096, rs4712959, rs4712960 and rs4712961) are single nucleotide polymorphisms. Minor allele frequency of 5'UTR variant rs4711096 was significantly lower in infertile men (p-value=1.67e-3; OR=0.65). The rare non-synonymous variant; rs368672899, p.Ser5Pro was seen in one oligoasthenoteratozoospermic individual. Interestingly, by mass spectrometry analysis this site on TSH2B was identified to bear a phosphate group in sperm of fertile men.Our study reveals a defect in replacement of somatic histones with testis-specific variants in infertile men. Chromatin compaction positively correlates with sperm motility suggestive of its utility in diagnostic semen analysis of infertile individuals. Our observations with TSH2B and its cognate gene in sperm of infertile men, indicates an essential role for TSH2B in meiosis and its phosphorylation in sperm motility, respectively.Copyright © 2022. Published by Elsevier Inc.

Citation

Aniket Patankar, Digumarthi V S Sudhakar, Rahul Gajbhiye, Suchitra Surve, Kumarasamy Thangaraj, Priyanka Parte. Proteomic and genetic dissection of Testis specific Histone 2B in infertile men reveals its contribution to meiosis and sperm motility. F&S science. 2022 Jul 12

PMID: 35840050

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