3oak
From Proteopedia
Crystal structure of a Spn1 (Iws1)-Spt6 complex
Structural highlights
Function[IWS1_YEAST] Transcription factor involved in RNA polymerase II transcription regulation. May function in both SPT15/TBP post-recruitment and recruitment steps of transcription.[1] [2] [SPT6_YEAST] Plays a role in maintenance of chromatin structure during RNA polymerase II transcription elongation thereby repressing transcription initiation from cryptic promoters. Mediates the reassembly of nucleosomes onto the promoters of at least a selected set of genes during repression; the nucleosome reassembly is essential for transcriptional repression. Essential for viability.[3] [4] [5] [6] Publication Abstract from PubMedEukaryotic transcription and mRNA processing depend upon the coordinated interactions of many proteins, including Spn1 and Spt6, which are conserved across eukaryotes, are essential for viability, and associate with each other in some of their biologically important contexts. Here we report crystal structures of the Spn1 core alone and in complex with the binding determinant of Spt6. Mutating interface residues greatly diminishes binding in vitro and causes strong phenotypes in vivo, including a defect in maintaining repressive chromatin. Overexpression of Spn1 partially suppresses the defects caused by an spt6 mutation affecting the Spn1 interface, indicating that the Spn1-Spt6 interaction is important for managing chromatin. Spt6 binds nucleosomes directly in vitro, and this interaction is blocked by Spn1, providing further mechanistic insight into the function of the interaction. These data thereby reveal the structural and biochemical bases of molecular interactions that function in the maintenance of chromatin structure. Structure and biological importance of the Spn1-Spt6 interaction, and its regulatory role in nucleosome binding.,McDonald SM, Close D, Xin H, Formosa T, Hill CP Mol Cell. 2010 Dec 10;40(5):725-35. Epub 2010 Nov 25. PMID:21094070[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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