spermatid nuclear transition protein 1,Stp,Stp-1,TP,Tp-,Tp-1,TP1.
Plays a key role in the replacement of histones to protamine in the elongating spermatids of mammals (PubMed:10781074, PubMed:15163613, PubMed:15189834, PubMed:15083521, PubMed:28366643). In condensing spermatids, loaded onto the nucleosomes, where it promotes the recruitment and processing of protamines, which are responsible for histone eviction (PubMed:28366643). The histone H2AFB1-HIST1H2BA/TH2B dimer is required for loading of TNP1 onto chromatin (PubMed:28366643).