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Purification of Xenopus laevis mitochondrial RNA polymerase and identification of a dissociable factor required for specific transcription

Journal Article · · Mol. Cell. Biol.; (United States)
DOI:https://doi.org/10.1128/MCB.8.7.2910· OSTI ID:6272689
The Xenopus laevis mitochondrial RNA (mtRNA) polymerase was purified to near homogeneity with an overall yield approaching 50%. The major polypeptides in the final fraction were a doublet of proteins of approximately 140 kilodaltons that copurified with the mtRNA polymerase activity. It appeared likely that the smaller polypeptide is a breakdown product of the larger one. The highly purified polymerase was active in nonspecific transcription but required a dissociable factor for specific transcription of X. laevis mtDNA. The factor could be resolved from mtRNA polymerase by hydrophobic chromatography and had a sedimentation coefficient of 3.0 S. The transcription factor eluted from both the hydrophobic column and a Mono Q anion-exchange column as a single symmetrical peak. The mtRNA polymerase and this factor together are necessary and sufficient for active transcription from four promoters located in a noncoding region of the mtDNA genome between the gene for tRNA/sup Phe/ and the displacement loop.
Research Organization:
Dept. of Pharmacology and Graduate Program in Genetics, State Univ. of New York at Stony Brook, Stony Brook, NY (US)
OSTI ID:
6272689
Journal Information:
Mol. Cell. Biol.; (United States), Journal Name: Mol. Cell. Biol.; (United States) Vol. 8:7; ISSN MCEBD
Country of Publication:
United States
Language:
English