Functional and Structural Dissection of the SWI/SNF Chromatin Remodeling Complex: A Dissertation

摘要: The yeast SWI/SNF complex is the prototype of a subfamily ATP-dependent chromatin remodeling complexes. It consists eleven stoichiometric subunits including Swi2p/Snf2p, Swi1p, Snf5p, Swi3p, Swp82p, Swp73p, Arp7p, Arp9p, Snf6p, Snf11p, and Swp29p, with molecular weight 1.14 mega Daltons. catalytic subunit SWI/SNF, evolutionally conserved from to human cells. Genetic evidence suggests that required for transcriptional regulation subset genes, especially inducible genes. can be recruited target promotors by gene specific activators, in some cases, facilitates activator binding. Biochemical studies have demonstrated purified hydrolyze ATP, it use energy ATP hydrolysis generate superhelical torsion, mobilize mononucleosomes, enhance accessibility endonucleases nucleosomal DNA, displace H2A/H2B dimers, induce dinucleosome altosome formation, or evict nucleosomes. A homolog BRG1, complex. Interestingly, isolated BRG1 alone able remodel mononucleosome substrate. Importantly, mutations mammalian core are implicated tumorigenesis. Therefore, remains interesting characterize role(s) each function. In this thesis project, I dissected function investigating role SANT domain Swi3p subunit. one components complex, contains an uncharacterized has been found many regulatory proteins. Earlier suggested Ada2p may serve as histone tail recognition module. For small deletion amino acids caused growth phenotype similar other swi/snf mutants. chapter I, reviewed recent findings complexes discuss mechanism their action. II, characterized Swi3p. defect genome-wide profile, recruitment, more interestingly impairment dissociation into several subcomplexes: 1) Swi2p/Arp7p/Arp9p, 2) Swi3p/Swp73p/Snf6p, 3) 4) Swi1p. Artificial tethering onto LacZ reporter promoter failed activate absence domain, although Swi2p promoter. We thus critical serves protein scaffold integrate these subcomplexes intact Chapter III, first enzymatic activity subcomplexes, minimal Swi2p/Arp7p/Arp9p. subcomplex fully functional assays…