title: The TFIIF-like Rpc37/53 dimer lies at the center of a protein network to connect TFIIIC, Bdp1, and the RNA polymerase III active center.
abstract: Eukaryotic RNA polymerase III (Pol III) relies on a transcription factor TFIIF-like Rpc37/53 subcomplex for promoter opening, elongation, termination, and reinitiation. By incorporating the photoreactive amino acid p-benzoyl-L-phenylalanine (BPA) into Rpc37, Rpc53, and the Rpc2 subunit of Pol III, we mapped protein-protein interactions, revealing the position of Rpc37/53 within the Pol III preinitiation complex (PIC). BPA photo-cross-linking was combined with site-directed hydroxyl radical probing to localize the Rpc37/53 dimerization module on the lobe/external 2 domains of Rpc2, in similarity to the binding of TFIIF on Pol II. N terminal to the dimerization domain, Rpc53 binds the Pol III-specific subunits Rpc82 and Rpc34, the Pol III stalk, and the assembly factor TFIIIC, essential for PIC formation. The C-terminal domain of Rpc37 interacts extensively with Rpc2 and Rpc34 and contains binding sites for initiation factor Bdp1. We also located the C-terminal domain of Rpc37 within the Pol III active center in the ternary elongation complex, where it likely functions in accurate termination. Our work explains how the Rpc37/53 dimer is anchored on the Pol III core and acts as a hub to integrate a protein network for initiation and termination.
authors.affiliation: Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, Republic of China.
authors.forename: Chih-Chien
authors.initials: CC
authors.lastname: Wu
authors.forename: Yu-Chun
authors.initials: YC
authors.lastname: Lin
authors.forename: Hung-Ta
authors.initials: HT
authors.lastname: Chen
mesh_terms: D020134:Catalytic Domain; D053858:Metabolic Networks and Pathways; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012320:RNA Polymerase III / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D035361:Transcription Factor TFIIIB / Q000378:metabolism*; D019473:Transcription Factors, TFII / Q000378:metabolism*; D019474:Transcription Factors, TFIII / Q000378:metabolism*; D014158:Transcription, Genetic; D000098832:Transcription Factor TFIIIC
chemical_list: C474805:Bdp1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035361:Transcription Factor TFIIIB; D019473:Transcription Factors, TFII; D019474:Transcription Factors, TFIII; D000098832:Transcription Factor TFIIIC; C508372:RPC37 protein, S cerevisiae; C508373:RPC53 protein, S cerevisiae; D012320:RNA Polymerase III; C056604:transcription factor TFIIF