Loss of the Rpb4/Rpb7 subcomplex in a mutant form of the Rpb6 subunit shared by RNA polymerases I, II, and III
| Autor: | Nancy A. Woychik, Meredith H. Prysak, Qian Tan |
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| Rok vydání: | 2003 |
| Předmět: |
Models
Molecular Saccharomyces cerevisiae Proteins Transcription Genetic Macromolecular Substances Protein Conformation Molecular Sequence Data RNA-dependent RNA polymerase RNA polymerase II Saccharomyces cerevisiae Fungal Proteins chemistry.chemical_compound RNA Polymerase I RNA polymerase RNA polymerase I Amino Acid Sequence RNA Messenger Molecular Biology RNA polymerase II holoenzyme Polymerase Conserved Sequence Transcriptional Regulation biology RNA Polymerase III Cell Biology DNA-Directed RNA Polymerases Molecular biology Protein Subunits chemistry Mutation biology.protein RNA Polymerase II Transcription factor II D Small nuclear RNA |
| Zdroj: | Molecular and cellular biology. 23(9) |
| ISSN: | 0270-7306 |
| Popis: | We have identified a conditional mutation in the shared Rpb6 subunit, assembled in RNA polymerases I, II, and III, that illuminated a new role that is independent of its assembly function. RNA polymerase II and III activities were significantly reduced in mutant cells before and after the shift to nonpermissive temperature. In contrast, RNA polymerase I was marginally affected. Although the Rpb6 mutant strain contained two mutations (P75S and Q100R), the majority of growth and transcription defects originated from substitution of an amino acid nearly identical in all eukaryotic counterparts as well as bacterial omega subunits (Q100R). Purification of mutant RNA polymerase II revealed that two subunits, Rpb4 and Rpb7, are selectively lost in mutant cells. Rpb4 and Rpb7 are present at substoichiometric levels, form a dissociable subcomplex, are required for RNA polymerase II activity at high temperatures, and have been implicated in the regulation of enzyme activity. Interaction experiments support a direct association between the Rpb6 and Rpb4 subunits, indicating that Rpb6 is one point of contact between the Rpb4/Rpb7 subcomplex and RNA polymerase II. The association of Rpb4/Rpb7 with Rpb6 suggests that analogous subunits of each RNA polymerase impart class-specific functions through a conserved core subunit. |
| Databáze: | OpenAIRE |
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