Post-meiotic gene activity in spermatogenesis of the mouse

Mouse male germ cells at middle-late pachytene and early spermatid stages obtained by velocity sedimentation at unit gravity in albumin gradients were labelled in culture with [3H]uridine. The newly synthesized RNAs extracted from polysomes of the 2 cell types were studied by sucrose gradient fractionation and poly(U) Sepharose chromatography. The results showed that round spermatids, as well as pachytene spermatocytes, synthesize both ribosomal and polyadenylated RNA molecules. Since these latter are engaged in polysomes they are presumably active messenger RNA molecules.