ATP-dependent machin Linker histones might brake the chromatin B ATP-dependent machi remodeling machine Linker histones are ATP-dependent machine ubiquitous components of cellular chromatin that constrain the entry/exit DNA of the nucleosome and incorporate another 20 bp of dNa into a particle called a chromatosome Linker histone or members of the polycomb group(PcG)of proteins are conserved from flies to mammals, and they are required for virtually elimination of remodeling activities of yeast SWI-SNF, human SWl-SNF, ACF and Mi-2 complexes EMBO Reports3,4,319322(2002)) 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 21 Linker histones are ubiquitous components of cellular chromatin that constrain the entry/exit DNA of the nucleosome and incorporate another 20 bp of DNA into a particle called a chromatosome. Linker histone or members of the polycomb group (PcG) of proteins are conserved from flies to mammals, and they are required for virtually elimination of remodeling activities of yeast SWI–SNF, human SWI–SNF, ACF and Mi-2 complexes . Linker histones might brake the chromatin remodeling machine (EMBO Reports 3, 4, 319–322 (2002) )
3. Chromatin remodelers 染色质重构复合物) Chromatin remodelers acquire energy through ATP hydrolysis to remodel chromatin Numerous chromatin remodeling complexes exits They differ in the core DNA-dependent ATPase subunit There is some sharing of factors between complexes and homologs between species There are 3 main classes(more could follow) 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 22 3. Chromatin remodelers (染色质重构复合物) • Chromatin remodelers acquire energy through ATP hydrolysis to remodel chromatin • Numerous chromatin remodeling complexes exits • They differ in the core DNA-dependent ATPase subunit • There is some sharing of factors between complexes and homologs between species •There are 3 main classes (more could follow)
Chromatin-remodeling complexes carry out key enzymatic activities, changing chromatin structure by altering DNA-histone contacts within a nucleosome in an ATP-dependent manner. These complexes can be divided into three classes on the basis of the similarities of their atpase subunits to the swi2/Snf2. swi and Mi-2 proteins 1. The SW12/SNF2 group 2.The ISWI group 3. The Mi-2 group: chromatin-remodeling and deacetylase complexes 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 23 Chromatin-remodeling complexes carry out key enzymatic activities, changing chromatin structure by altering DNA–histone contacts within a nucleosome in an ATP-dependent manner. These complexes can be divided into three classes on the basis of the similarities of their ATPase subunits to the Swi2/Snf2, ISWI, and Mi-2 proteins. 1. The SWI2/SNF2 group. 2. The ISWI group 3. The Mi-2 group: chromatin-remodeling and deacetylase complexes
ATP-dependent Chromatin Remodeling Complex First identified in yeast Yeast complex known as sWI/SNF Human complexes are BRM and BRG1 2-12 subunits protein complex Function suppressed by histone and other chromatin components Relieves chromatin-mediated suppression of a set of inducible genes Important for genes expressed in late anaphase When chromatin condensation is not yet fully reversed after mitosis 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 24 First identified in yeast – Yeast complex known as SWI/SNF – Human complexes are BRM and BRG1 – 2~12 subunits protein complex • Function suppressed by histone and other chromatin components • Relieves chromatin-mediated suppression of a set of inducible genes • Important for genes expressed in late anaphase – When chromatin condensation is not yet fully reversed after mitosis ATP-dependent Chromatin Remodeling Complex
Chromatin Remodeling Complexes SWUSNF Yeast. SWISNF RSC Drosophila. dSW/SNF Human: Brm, Brg ATP Yeast /SW1/sW2 SWi/sNF Drosophila. NURF ISWI Mi-2 CHRAC. ACF Human WCRFIACF ADI RSF NORC Pi ■Mi-2cHD-1 Drosophila dNURD Human NUrD 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 25 Chromatin Remodeling Complexes SWI/SNF: – Yeast: SWI/SNF, RSC – Drosophila: dSWI/SNF – Human: Brm, Brg ISWI: – Yeast: ISW1, ISW2 – Drosophila: NURF, CHRAC, ACF – Human: WCRF/ACF, RSF, NORC Mi-2/CHD-1 – Drosophila: dNuRD – Human: NuRD ATP ADP + Pi Swi/SNF, ISWI, Mi-2