Detection of G-C rich heterochromatin by 5-azacytidine in mammals.

A new effect of 5-ACR (5-azacytidine), observed in fibroblast or kidney cell cultures is described in the calf (Bos taurus) and in some selected primates (Cebus capucinus, Erythrocebus patas, and Cercopithecus cephus). This cytidine analogue, used at low doses during the last late S phase, prevents the condensation of R-band positive heterochromatin (G-C rich segments). Thus, 5-ACR treatment can be used as a simple method for the detection of G-C rich heterochromatin.