title: Yeast mitochondrial RNAP conformational changes are regulated by interactions with the mitochondrial transcription factor.
abstract: Mitochondrial RNA polymerases (MtRNAPs) are members of the single-subunit RNAP family, the most well-characterized member being the RNAP from T7 bacteriophage. MtRNAPs are, however, functionally distinct in that they depend on one or more transcription factors to recognize and open the promoter and initiate transcription, while the phage RNAPs are capable of performing these tasks alone. Since the transcriptional mechanisms that are conserved in phage and mitochondrial RNAPs have been so effectively characterized in the phage enzymes, outstanding structure-mechanism questions concern those aspects that are distinct in the MtRNAPs, particularly the role of the mitochondrial transcription factor(s). To address these questions we have used both negative staining and cryo-EM to generate three-dimensional reconstructions of yeast MtRNAP initiation complexes with and without the mitochondrial transcription factor (MTF1), and of the elongation complex. Together with biochemical experiments, these data indicate that MTF1 uses multiple mechanisms to drive promoter opening, and that its interactions with the MtRNAP regulate the conformational changes undergone by the latter enzyme as it traverses the template strand.
authors.affiliation: Department for Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Madrid 28049, Spain.
authors.forename: Srdja
authors.initials: S
authors.lastname: Drakulic
authors.affiliation: Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas, TX 78229-3900, USA.
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department for Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Madrid 28049, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Cuéllar
authors.affiliation: Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas, TX 78229-3900, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas, TX 78229-3900, USA.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Velázquez
authors.affiliation: Department for Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Madrid 28049, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: Martín-Benito
authors.affiliation: Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas, TX 78229-3900, USA sousa@biochem.uthscsa.edu.
authors.forename: Rui
authors.initials: R
authors.lastname: Sousa
authors.affiliation: Department for Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Madrid 28049, Spain jmv@cnb.csic.es.
authors.forename: José M
authors.initials: JM
authors.lastname: Valpuesta
mesh_terms: D004247:DNA / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry*; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry; D008928:Mitochondria / Q000201:enzymology / Q000235:genetics*; D024101:Mitochondrial Proteins / Q000737:chemistry*; D008958:Models, Molecular; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D061805:Transcription Elongation, Genetic; D014157:Transcription Factors / Q000737:chemistry*; D061785:Transcription Initiation, Genetic; D015003:Yeasts / Q000201:enzymology
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D024101:Mitochondrial Proteins; D014157:Transcription Factors; C422562:mitochondrial transcription factor A; D004247:DNA; D012321:DNA-Directed RNA Polymerases