BIOCHEMICAL-ANALYSIS OF CHROMATIN STRUCTURE AND FUNCTION USING DROSOPHILA EMBRYO EXTRACTS

The biochemical analysis of chromatin structure and function is greatl y facilitated by the availability of cell-free systems that assemble c hromatin under physiological conditions. One such system that has show n great potential is derived from extracts of early Drosophila embryos . These embryos contain large maternal stocks of chromatin constituent s, such as histones and assembly factors. Chromatin assembled in these extracts resembles native chromatin in many respects: it displays phy siological nucleosome repeat lengths, it is complex, containing a weal th of nonhistone proteins as well as enzymatic activities, and it has dynamic properties that allow the interaction of DNA-binding proteins that regulate important cellular processes. Most importantly, chromati n with variant properties, e.g., with respect to the basic geometry of the nucleosomal array, histone modifications, and its content of link er histones or nonhistone proteins, can be obtained by manipulating th e reconstitution conditions. The synthesis of uniform chromatin with s pecific characteristics should allow the analysis of the functional si gnificance of the structural and biochemical heterogeneity observed in vivo. (C) 1997 Academic Press.