A model for the control of transcription during development.
In order to account for the coordinate expression of large numbers of genes that must occur during development and differentiation, a mechanism of transcription control distinct from those operating in bacteria is proposed. Transcription would be initiated by small RNA chains that would function as primers for elongation. A given species of primer RNA generated by a primary induction event would bind by complementary base pairing to a variety of sites in the genome and thus trigger the transcription of adjacent structural genes. The primer RNA region would be excised from the transcription products in the nucleus, and possibly be reutilized as primers for transcription. This model can account for the occurrence of tissue-specific nuclear RNA complementary to repetitive DNA and does not require that the major RNA polymerases be capable of initiation. A minor RNA polymerase capable of initiating primer RNA chains and subject to conventional transcription controls would be required. Carcinogenesis, which is accompanied in many cases by the appearance of a variety of embryonic antigens, could involve the induction of RNA primers normally programmed to function early in development.
D000818:Animals; D002454:Cell Differentiation; D012321:DNA-Directed RNA Polymerases; D005796:Genes; D008954:Models, Biological; D009374:Neoplasms, Experimental / Q000209:etiology*; D012313:RNA; D014158:Transcription, Genetic
D012313:RNA; D012321:DNA-Directed RNA Polymerases