Autoradiographic Evidence of Synthesis of an Arginine-rich Histone during Spermiogenesis in Drosophila melanogaster

Abstract

THE DNA-associated protein of the animal spermatozoon customarily undergoes two major changes in the course of differentiation of this cell during spermato-genesis. These changes, as have been established in a variety of organisms, are cytochemically delineable by the alkaline-fast-green, picric acid-bromophenol blue, and ammoniacal-silver staining methods^1–4, when used in conjunction with the procedures of deamination and acetylation^5–7. The first of these changes relates to the replacement of a lysine-rich histone by one rich in arginine in the spermatid stage of development of the spermatozoon, and the second change reflects the acquisition of protamine in place of the arginine-rich histone by the maturing spermatozoon. In Drosophila melanogaster however, there is observed only the first of these protein transformations^8,9, and this occurs, according to our observations, at the terminal stages of spermiogenesis, shortly before eclosion of the fly (within 24 h or so at 29° C); that is, the time of the arginine-histone shift during sperm development in D. melanogaster coincides with the second stage of these chemical alterations in some other organisms, and there is no subsequent change to protamine in the mature spermatozoon.