Research on the interplay between chromatin and transcription has prog
ressed along three lines during the past year. Evidence has been repor
ted for disruption of nucleosomes by transcriptional regulatory protei
ns in cell-free systems; displacement of the histone octamer during tr
anscription has been conclusively demonstrated; and insights into tran
scriptional repression by heterochromatin have been gained from studie
s of silent mating loci and telomeres in yeast.