Hydrozoan sperm-specific SPKK motif-containing histone H2B variants stabilise chromatin with limited compaction.

ABSTRACT: Many animals achieve sperm chromatin compaction and stabilisation by replacing canonical histones with sperm nuclear basic proteins (SNBPs) such as protamines during spermatogenesis. Hydrozoan cnidarians and echinoid sea urchins lack protamines and have evolved a distinctive family of sperm-specific histone H2Bs (spH2Bs) with extended N termini rich in SPK(K/R) motifs. Echinoid sperm packaging is regulated by spH2Bs. Their sperm is negatively buoyant and fertilises on the sea floor. Hydroid cnidarians undertake broadcast spawning but their sperm properties are poorly characterised. We show that Hydractinia echinata and H. symbiolongicarpus sperm chromatin possesses higher stability than somatic chromatin, with reduced accessibility to transposase Tn5 integration and to endonucleases in vit

SUBMITTER: Torok A 

PROVIDER: S-EPMC9903204 | biostudies-literature | 2023 Jan

REPOSITORIES: biostudies-literature