The function of ENSG00000197651 (CCER1, coiled-coil glutamate rich protein 1) is as follows. Regulator of histone epigenetic modifications and chromatin compaction into the sperm head, required for histone-to-protamine (HTP) transition. HTP is a key event in which somatic histones are first replaced by testis-specific histone variants, then transition proteins (TNPs) are incorporated into the spermatid nucleus, and finally protamines (PRMs) replace the TNPs to promote chromatin condensation. .