TY - JOUR
T1 - Specificity of release by Escherichia coli transcription termination factor rho of nascent mRNA transcripts initiated at the λ P(R) promoter
AU - Morgan, W. D.
AU - Bear, D. G.
AU - Von Hippel, P. H.
PY - 1984
Y1 - 1984
N2 - We have studied the specificity and kinetics of release of nascent RNA from ternary transcription complexes by Escherichia coli transcription termination factor rho in vitro. Stable ternary complexes, initiated at the λ P(R) promoter, were prepared either by quenching the elongation reaction with EDTA or by preventing further elongation by incorporating 3'-O-methyl nucleotides at the 3' end of the nascent RNA chains. We find that rho protein can only release λ P(R)-initiated transcripts from ternary complexes in which transcription has proceeded beyond 288 base pairs from P(R); shorter chains are not released. Substitution of inosine for guanosine in the nascent RNA permits the rho-dependent release process to operate on complexes located as close as 108-116 base pairs downstream from P(R). The regions of the template from which rho can release transcripts correspond, for both guanosine- and inosine-containing RNA, to those within which rho-dependent termination has also been shown to occur (Morgan, W.D., Bear, D.G., and von Hippel, P.H. (1983) J. Biol. Chem. 258, 9553-9564, 9565-9574). The half-time for the major part of the release process is less than 10 s. These results are in good accord with the hypothesis that the specificity of rho-dependent termination is jointly determined by two separable processes: (i) the specificity of rho binding to the nascent RNA chain and (ii) the location and strength of RNA polymerase-pausing sites.
AB - We have studied the specificity and kinetics of release of nascent RNA from ternary transcription complexes by Escherichia coli transcription termination factor rho in vitro. Stable ternary complexes, initiated at the λ P(R) promoter, were prepared either by quenching the elongation reaction with EDTA or by preventing further elongation by incorporating 3'-O-methyl nucleotides at the 3' end of the nascent RNA chains. We find that rho protein can only release λ P(R)-initiated transcripts from ternary complexes in which transcription has proceeded beyond 288 base pairs from P(R); shorter chains are not released. Substitution of inosine for guanosine in the nascent RNA permits the rho-dependent release process to operate on complexes located as close as 108-116 base pairs downstream from P(R). The regions of the template from which rho can release transcripts correspond, for both guanosine- and inosine-containing RNA, to those within which rho-dependent termination has also been shown to occur (Morgan, W.D., Bear, D.G., and von Hippel, P.H. (1983) J. Biol. Chem. 258, 9553-9564, 9565-9574). The half-time for the major part of the release process is less than 10 s. These results are in good accord with the hypothesis that the specificity of rho-dependent termination is jointly determined by two separable processes: (i) the specificity of rho binding to the nascent RNA chain and (ii) the location and strength of RNA polymerase-pausing sites.
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M3 - Article
C2 - 6330119
AN - SCOPUS:0021262602
SN - 0021-9258
VL - 259
SP - 8664
EP - 8671
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 13
ER -