title: Characterization of the interactions of mammalian RNA polymerase I associated proteins PAF53 and PAF49.
abstract: Masami Muramatsu's laboratory demonstrated the critical role of RNA polymerase I (Pol I)-associated factor PAF53 in mammalian rRNA transcription. They have also identified a second polymerase associated factor, PAF49. Both PAF49 and PAF53 copurify with that fraction of the RNA polymerase I molecules that can function in transcription initiation in vitro. PAF49 and PAF53 are the mammalian homologues of two subunits of yeast RNA polymerase I, A34.5 and A49, that form a TFIIF-related subcomplex in yeast RNA polymerase I. In light of those publications, we investigated the interactions between various deletion and substitution mutants of mammalian PAF49 and PAF53 with the purpose of identifying those domains of the mammalian proteins that interact. Comparison of our results with structural studies on yeast A34.5 and A49 demonstrates that the yeast and mammalian proteins may in fact share structural similarities. In fact, the deletion mutagenesis data confirmed and extended the structural studies. For example, amino acids 41-86 of PAF49 were sufficient to provide the basis for heterodimerization. In silico structural analysis predicted that this region could assume a structure similar to the homologous region of yeast A34.5. Those similarities are insufficient, by themselves, for the proteins to form interspecific heterodimers. However, substitution of amino acids 52-98 of yeast A34.5 with amino acids 41-86 of mammalian PAF49 resulted in a protein that could heterodimerize with mouse PAF53.
authors: Department of Cell Biology, University of Oklahoma College of Medicine, Oklahoma City, OK 73104, USA.
authors: Yvonne
authors: Y
authors: Penrod
authors: Katrina
authors: K
authors: Rothblum
authors: Lawrence I
authors: LI
authors: Rothblum
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D025941:Protein Interaction Mapping; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D012318:RNA Polymerase I / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D009687:Nuclear Proteins; C488429:PAF49 protein, mouse; C484388:Paf53 protein, mouse; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012318:RNA Polymerase I