5n9g
From Proteopedia
TFIIIB -TBP/Brf2/DNA and SANT domain of Bdp1-
Structural highlights
Disease[TBP_HUMAN] Defects in TBP are the cause of spinocerebellar ataxia type 17 (SCA17) [MIM:607136]. Spinocerebellar ataxia is a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCA17 is an autosomal dominant cerebellar ataxia (ADCA) characterized by widespread cerebral and cerebellar atrophy, dementia and extrapyramidal signs. The molecular defect in SCA17 is the expansion of a CAG repeat in the coding region of TBP. Longer expansions result in earlier onset and more severe clinical manifestations of the disease.[1] [2] [3] Function[BRF2_HUMAN] General activator of RNA polymerase III transcription. Factor exclusively required for RNA polymerase III transcription of genes with promoter elements upstream of the initiation sites.[4] [5] [6] [BDP1_HUMAN] General activator of RNA polymerase III transcription. Requires for transcription from all three types of polymerase III promoters. Requires for transcription of genes with internal promoter elements and with promoter elements upstream of the initiation site.[7] [TBP_HUMAN] General transcription factor that functions at the core of the DNA-binding multiprotein factor TFIID. Binding of TFIID to the TATA box is the initial transcriptional step of the pre-initiation complex (PIC), playing a role in the activation of eukaryotic genes transcribed by RNA polymerase II. Component of the transcription factor SL1/TIF-IB complex, which is involved in the assembly of the PIC (preinitiation complex) during RNA polymerase I-dependent transcription. The rate of PIC formation probably is primarily dependent on the rate of association of SL1 with the rDNA promoter. SL1 is involved in stabilization of nucleolar transcription factor 1/UBTF on rDNA.[8] Publication Abstract from PubMedInitiation of gene transcription by RNA polymerase (Pol) III requires the activity of TFIIIB, a complex formed by Brf1 (or Brf2), TBP (TATA-binding protein), and Bdp1. TFIIIB is required for recruitment of Pol III and to promote the transition from a closed to an open Pol III pre-initiation complex, a process dependent on the activity of the Bdp1 subunit. Here, we present a crystal structure of a Brf2-TBP-Bdp1 complex bound to DNA at 2.7 A resolution, integrated with single-molecule FRET analysis and in vitro biochemical assays. Our study provides a structural insight on how Bdp1 is assembled into TFIIIB complexes, reveals structural and functional similarities between Bdp1 and Pol II factors TFIIA and TFIIF, and unravels essential interactions with DNA and with the upstream factor SNAPc. Furthermore, our data support the idea of a concerted mechanism involving TFIIIB and RNA polymerase III subunits for the closed to open pre-initiation complex transition.Transcription initiation by RNA polymerase III requires TFIIIB, a complex formed by Brf1/Brf2, TBP and Bdp1. Here, the authors describe the crystal structure of a Brf2-TBP-Bdp1 complex bound to a DNA promoter and characterize the role of Bdp1 in TFIIIB assembly and pre-initiation complex formation. Molecular mechanisms of Bdp1 in TFIIIB assembly and RNA polymerase III transcription initiation.,Gouge J, Guthertz N, Kramm K, Dergai O, Abascal-Palacios G, Satia K, Cousin P, Hernandez N, Grohmann D, Vannini A Nat Commun. 2017 Jul 25;8(1):130. doi: 10.1038/s41467-017-00126-1. PMID:28743884[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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