5-AZA DEOXYCYTIDINE-INDUCED INHIBITION OF DIFFERENTIATION OF SPERMATOGONIA INTO SPERMATOCYTES IN THE MOUSE

In order to explore the significance of DNA methylation in proliferati on and differentiation of germ cells in testis, 5-aza,2'-deoxyCytidine (5-azaCdR), a hypomethylating agent, was administered in vivo to neon atal mice having only spermatogonial (premeiotic) cells. End-labeling of the Mspl, Hpall, and Hhal digested DNA revealed considerable loss o f methylation following the treatment. Cellular and histological prepa rations of the testis showed complete inhibition of differentiation in to spermatocytic stage. Analysis of protein synthesis in the treated a nd control testis by growing the cells in S-35-Methionine medium and r esolving the lysate by SDS-PAGE revealed that the programme of express ion of at least 5 polypeptides (35.0, 31.5, 27.0, 22.5, and 18.0 KD) w as altered as a result of 5-azaCdR incorporation. It appears that DNA methylation plays a critical role in the differentiation of gonia into primary spermatocytes. (C) 1995 Wiley-Liss, Inc.