9604154 Perry The protein CHD1 is associated with transcriptionally active regions of extended (decompacted) interphase chromatin. The structural features of this protein have been preserved over a long period of evolution, suggesting that it performs analogous functions in organisms as diverse as yeast, flies and mammals. These features include a chromo domain, relating it to proteins like HP1 and Polycomb; an ATPase/helicase domain, relating it to proteins like SNF2/SWI2 and Brahma; and a DNA-binding domain that specifically interacts with the minor groove of A(T-rich DNA. This research is aimed at gaining deeper insight into the roles played by CHD1 and its associated proteins in the remodeling of chromatin structure and the regulation of gene expression. Experiments with Drosophila, in which several target genes of CHD1 activity have been identified, will include (i) immunocytochemical localization studies of polytene chromosomes from flies in different developmental and physiological states; (ii) genetic studies of the consequences of directed mutations in the signature domains of CHD1; (iii) determination of the particular regions of target genes that interact with CHD1; and (iv) a genetic screen for CHD1 mutants and for enhancers and/or suppressors of these mutations. This research should contribute substantially to the knowledge of gene regulation. In particular, it should help illuminate mechanisms by which modifications of chromatin structure determine accessibility to the transcriptional apparatus. %%% The protein CHD1 is associated with transcriptionally active regions of extended (decompacted) interphase chromatin. The structural features of this protein have been preserved over a long period of evolution, suggesting that it performs analogous functions in organisms as diverse as yeast, flies and mammals. This research is aimed at gaining deeper insight into the roles played by CHD1 and its associated proteins in the remodeling of chromatin structure and the regulation o f gene expression. In particular, it should help illuminate mechanisms by which modifications of chromatin structure determine accessibility to the transcriptional apparatus. ***
