Comparison of the RNA polymerase III transcription machinery in Schizosaccharomyces pombe, Saccharomyces cerevisiae and human.
Multi-subunit transcription factors (TF) direct RNA polymerase (pol) III to synthesize a variety of essential small transcripts such as tRNAs, 5S rRNA and U6 snRNA. Use by pol III of both TATA-less and TATA-containing promoters, together with progress in the Saccharomyces cerevisiae and human systems towards elucidating the mechanisms of actions of the pol III TFs, provides a paradigm for eukaryotic gene transcription. Human and S.cerevisiae pol III components reveal good general agreement in the arrangement of orthologous TFs that are distributed along tRNA gene control elements, beginning upstream of the transcription initiation site and extending through the 3' terminator element, although some TF subunits have diverged beyond recognition. For this review we have surveyed the Schizosaccharomyces pombe database and identified 26 subunits of pol III and associated TFs that would appear to represent the complete core set of the pol III machinery. We also compile data that indicate in vivo expression and/or function of 18 of the fission yeast proteins. A high degree of homology occurs in pol III, TFIIIB, TFIIIA and the three initiation-related subunits of TFIIIC that are associated with the proximal promoter element, while markedly less homology is apparent in the downstream TFIIIC subunits. The idea that the divergence in downstream TFIIIC subunits is associated with differences in pol III termination-related mechanisms that have been noted in the yeast and human systems but not reviewed previously is also considered.
Huang
Y
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Laboratory of Molecular Growth Regulation, National Institute of Child Health and Human Development, National Institutes of Health, 6 Center Drive MSC 2753, Bethesda, MD 20892-2753, USA.
Maraia
R J
RJ
D000595:Amino Acid Sequence; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D019992:Databases as Topic; D005816:Genetic Complementation Test; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D021122:Protein Subunits; D012320:RNA Polymerase III / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics; D035181:TATA-Box Binding Protein; D035582:Transcription Factor TFIIIA; D035361:Transcription Factor TFIIIB; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism; D019474:Transcription Factors, TFIII / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D000098832:Transcription Factor TFIIIC
D002843:Chromatin; D004268:DNA-Binding Proteins; D021122:Protein Subunits; D035181:TATA-Box Binding Protein; D035582:Transcription Factor TFIIIA; D035361:Transcription Factor TFIIIB; D014157:Transcription Factors; D019474:Transcription Factors, TFIII; D000098832:Transcription Factor TFIIIC; D012320:RNA Polymerase III