Roles of transition nuclear proteins in spermiogenesis

摘要: The transition nuclear proteins (TPs) constitute 90% of the chromatin basic during steps spermiogenesis between histone removal and deposition protamines. We first summarize properties two major proteins, TP1 TP2, present concepts, based on their time appearance in vivo vitro properties, regarding roles. Distinct roles for TPs displacement, sperm shaping, condensation, maintenance DNA integrity have been proposed. More definitive information has recently obtained using mice with null mutations Tnp1 or Tnp2 genes respectively. In these mice, displacement shaping appear to progress quite normally. Spermatid condensation occurs, albeit an abnormal fashion, mature Tnp -null mutants are not as condensed wild-type sperm. There is also evidence that from mutant contain elevated level strand breaks. showed several unexpected phenotypes, including a high incidence configurational defects, such heads bent back midpieces, midpieces hairpin configurations, coils, clumps, other midpiece reduced levels proteolytic processing protamine 2 maturation, motility. partly compensate each both - were able produce offspring, largely overlapping functions had similar phenotypes.