The nucleosome can be restructured by two mechanisms the modification of core histones by histone acetyltransferases, deactylases, methyltrans ferases. and kinases 2. the movement of nucleosomes along DNA Which is carried out by ATP-dependent chromatin remodeling complexes The purpose of the chromatin remodeling proteins is to alter the nucleosome architecture such that genes are exposed to or hidden from the transcriptional machinery 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 11 The nucleosome can be restructured by two mechanisms 1. the modification of core histones by histone acetyltransferases, deactylases, methyltransferases, and kinases. 2. the movement of nucleosomes along DNA which is carried out by ATP-dependent chromatin remodeling complexes. The purpose of the chromatin remodeling proteins is to alter the nucleosome architecture such that genes are exposed to or hidden from the transcriptional machinery
Chromatin Modification and Remodeling ATP-independent, covalent modifications CH3 Ac Pi HATS. HDACs X0p oMn . Methylases -Ub . Kinases CH3 Ubiquitin Ligases ATP-dependent remodeling Chromatin remodelers ATP ADP /0X00 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 12 Chromatin Modification and Remodeling Chromatin Modification and Remodeling •ATP-independent, covalent modifications Ac Ub Pi Ac CH3 CH3 •HAT’s, HDAC’s •Methylases •Kinases •Ubiquitin Ligases ATP ADP + Pi •ATP-dependent remodeling Chromatin remodelers
Slent chromatin Cis elements Trans elements ∧、m Remodeling ∧今 Histone- modification enzyme 口fa6 ption factor Transcriptionally active chromatin 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 13
QNX Cis elements TATa box Histone Ac Early events in preparation for the expression of a gene in a mitotic chromosome likely include Dissociation of H1 Acetylation and partial decondensation of the chromatin 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 14 Ac Ac Ac Cis Histone 1 elements TATA box Early events in preparation for the expression of a gene in a mitotic chromosome likely include: • Dissociation of H1 • Acetylation and partial decondensation of the chromatin
Ac QO Activator Chromatin remodeler Histone acetylase The partially decondensed chromatin probably allows recruitment of select transcriptional activators, which, in turn, recruit Chromatin remodelers Additional histone modification enzymes The order of recruitment is not known 2005-10-29 Chaoqun Wu, Fudan University
2005-10-29 Chaoqun Wu, Fudan University Chaoqun Wu, Fudan University 15 Ac Ac Ac Ac Ac Chromatin remodeler Histone acetylase Ac Ac Ac Activator The partially decondensed chromatin probably allows recruitment of select transcriptional activators, which, in turn, recruit • Chromatin remodelers • Additional histone modification enzymes • The order of recruitment is not known