The topology of transcription by immobilized polymerases.
Current models for RNA synthesis involve an RNA polymerase that tracks along a static template. However, research on chromatin loops suggests that the template slides past a polymerase immobilized in a large transcription factory. The evidence for immobilized polymerases is reviewed, and a model for transcription by such fixed enzymes is presented. According to the model, gene activation would involve reducing gene-factory distance and increasing the affinity of a promoter for a factory. Locus controlling regions and enhancers would attach to a factory and increase the chances that a promoter could bind to a polymerase; after transcriptional termination, the gene would detach from the factory. As some RNA processing occurs cotranscriptionally, processing sites are also likely to be associated with the factory.
Iborra
F J
FJ
CRC Nuclear Structure and Function Research Group, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, United Kingdom. Peter.Cook@Path.OX.AC.UK
Pombo
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McManus
J
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Jackson
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Cook
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D004247:DNA / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004800:Enzymes, Immobilized; D005786:Gene Expression Regulation; D008957:Models, Genetic; D011401:Promoter Regions, Genetic; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D004800:Enzymes, Immobilized; D012313:RNA; D004247:DNA; D012321:DNA-Directed RNA Polymerases