Open AccessA stable transcription complex directs mouse ribosomal RNA synthesis by RNA polymerase I
Author(s) -
Valeria Cizewski,
Barbara SollnerWebb
Publication year - 1983
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/11.20.7043
Subject(s) - biology , transcription preinitiation complex , transcription (linguistics) , transcription factor ii e , dna , ribosomal rna , transcription factor ii f , general transcription factor , rna , rna polymerase i , microbiology and biotechnology , transcription bubble , rna polymerase , genetics , gene , promoter , gene expression , linguistics , philosophy
Ribosomal RNA is synthesized from template molecules that are activated by a stable association with essential transcription factors. This activated template assembles prior to the onset of transcription as a preinitiation complex and factors remain firmly attached during active elongation as well. Sequential addition of differently marked rRNA genes to an S-100 mouse cell extract shows that the DNA binding factors of the stable complex are present in limiting quantities. They associate rapidly with template molecules and the resultant transcription complex remains intact over prolonged periods of incubation in the presence of competitor DNA. The resistance of the stable complex to the usual inhibitory effect of high DNA concentration suggests that more than one DNA binding factor recognizes the rDNA promoter region and is needed to direct faithful transcription. Finally, although the stable complex is specific for the rRNA initiation region, added vector sequences can neutralize nonspecific DNA binding components that are also present in the cell extract. This lowers the requirement for rDNA template and demonstrates that each activated rRNA gene can direct at least 10 rounds of elongation and reinitiation.