Linker histone binding and displacement: versatile mechanism for transcriptional regulation

In recent years, the connection between chromatin structure and its transcr iptional activity has attracted considerable experimental effort. The post- translational modifications to both the core histones and the linker histon es are finely tuned through interactions with transcriptional regulators an d change chromatin structure in a way to allow transcription to occur. Here we review evidence for the involvement of linker histones in transcription al regulation and suggest a scenario in which the reversible and controllab le binding/displacement of proteins of this class to the nucleosome entry/e xit point determine the accessibility of the nucleosomal DNA to the transcr iptional machinery.