Regulation of Recombination by Chromatin

Abstract

Eukaryotic DNA is bound by various proteins such as histones, and is packaged into a highly condensed structure termed chromatin, which poses profound influences on DNA and its metabolism. Due to its compactness, chromatin generally represses all DNA-templated reactions by preventing DNA-processing proteins from accessing to and/or functioning at their target sites. On the contrary, there are many cases in which condensed chromatin rather facilitates genomic events through forming specific three-dimensional structures, promoting DNA-protein interactions, or bringing separately located loci together. Therefore, chromatin is a central regulator of DNA-dependent processes, and deciphering its roles is of paramount importance to understand their in vivo mechanisms. Obviously, recombination is under a great impact of chromatin, and much effort has been made to reveal how it is regulated by chromatin. In this chapter, we focus on three instances, homologous recombination, V(D)J recombination in vertebrates, and mating-type switching in fission yeast, to discuss a wide variety of roles of chromatin in regulating these events.