Characterisation of a human sperm cell subpopulation marked by the presence of the TSH2B histone

Abstract

During the process of mammalian spermiogenesis, a significant reorganisation of the chromatin structure occurs involving the sequential substitution of somatic histones with protamines. In the human sperm nucleus, approximately 15% of the basic nuclear protein complement is maintained as histones. Human testis/sperm-specific histone H2B (hTSH2B) is a variant of the histone H2B expressed exclusively in spermatogenic germline cells and present in some mature sperm cells. Thus, this protein marks a subpopulation of sperm cells in the ejaculate. Using indirect immunofluorescence, we examined the influence of hTSH2B on zona pellucida binding and sperm head decondensation in amphibian egg cell-free extract. As suggested by previous studies, we found that hTSH2B can be localised in only approximately 30% of sperm cells within a given ejaculate. We established that the presence of hTSH2B does not influence sperm zona pellucida binding capacity. Finally, we found that decondensation occurred more rapidly and to a greater extent in those cells containing hTSH2B. We propose that the presence or absence of hTSH2B within spermatozoa influences pronuclei formation and the activation of paternal genes following fertilisation and during early embryonic development.

Developmental sperm contributions: fertilization and beyond

“…Human testis/sperm-specific histone H2B (hTSH2B) is a variant of the histone H2B expressed exclusively in spermatogenic germline cells and present in some mature sperm cells. Thus, this protein marks a subpopulation of sperm cells in the ejaculate (165,166). Using indirect immunofluorescence, Singleton et al (165) examined the influence of hTSH2B on ZP binding and sperm head decondensation in amphibian egg cell-free extract.…”

Poly(ADP-ribose) Metabolism Is Essential for Proper Nucleoprotein Exchange During Mouse Spermiogenesis

“…Sperm smears were air dried and stored at À208C until use when they were rehydrated with PBS and then partially decondensed for immunostaining as described previously [41]. Briefly, decondensation solution (10 mM DTT, 200 international units of heparin, 0.2% Triton-X/ml in PBS) were layered onto the slide for 8 min at room temperature; and then the slides were fixed with 4% neutral paraformaldehyde for 15 min at room temperature.…”

Exposure to Bleomycin, Etoposide, and Cis-Platinum Alters Rat Sperm Chromatin Integrity and Sperm Head Protein Profile1

“…Recent findings have shown that the distribution of residual histones in sperm nuclei is not arbitrary but appears to be organized in a particular fashion such that their association with promoters of key gene regulators is preferentially maintained [12]. Abnormal histone retention or protamine deficiency in sperm is associated with a reduction in fertility and an increased risk of embryonic failure after fertilization [13,14]. Besides protamines and residual histones, other sperm head proteins may be in close association with sperm chromatin and play a crucial role in normal sperm function.…”