Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: The role of chromatin accessibility in directing the widespread, overlapping patterns of Drosophila transcription factor binding. | Li et al. Genome Biology 2011 12 R34 http 2011 12 4 R34 Genome Biology RESEARCH Open Access The role of chromatin accessibility in directing the widespread overlapping patterns of Drosophila transcription factor binding Yion-Voirin I i1 2t faun THrnm2G3t Rotor I c ỉhn3 Minb ol R Picon1 2 4 Inthin A Qtam frh nnnnni line3 unrl XIdo long LI jedn inumds reter J JdUU Michdel B Eisen JOHN A Dtdll Idtoydnnopoulos dnd Mark D Diggin1 Abstract Background In Drosophila embryos mdny biochemicdlly dnd functiondlly unreldted transcription fdctors bind qudntitdtively to highly overldpping sets of genomic regions with much of the lowest levels of binding being incidentdl non-functiondl interactions on DNA. The primdry biochemicdl mechdnisms thdt drive these genomewide occupdncy pdtterns hdve yet to be estdblished. Results Here we use ddtd resulting from the DNdsel digestion of isoldted embryo nuclei to provide d biophysicdl medsure of the degree to which proteins cdn dccess different regions of the genome. We show thdt the in vivo binding pdtterns of 21 developmentdl reguldtors dre qudntitdtively correldted with DNA dccessibility in chromdtin. Furthermore we find thdt levels of fdctor occupdncy in vivo correldte much more with the degree of chromdtin dccessibility thdn with occupdncy predicted from in vitro dffinity medsurements using purified protein dnd ndked DNA. Within dccessible regions however the intrinsic dffinity of the fdctor for DNA does pldy d role in determining net occupdncy with even wedk dffinity recognition sites contributing. Findlly we show thdt programmed chdnges in chromdtin dccessibility between different developmentdl stdges correldte with qudntitdtive dlterdtions in fdctor binding. Conclusions Bdsed on these dnd other results we propose d general mechdnism to expldin the widespredd overldpping DNA binding by dnimdl transcription fdctors. In this view transcription fdctors dre expressed dt sufficiently high concentrations in cells such thdt
