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Host factor requirements for processive antitermination of transcription and suppression of pausing by the N protein of bacteriophage lambda
The N protein of phage lambda prevents termination of transcription by Escherichia coli RNA polymerase at Rho-dependent and -independent terminators in the lambda early operons. The modification of RNA polymerase by N requires an N-utilization (nut) site, present in each lambda early operon, and inv...
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Published in: | The Journal of biological chemistry 1992-09, Vol.267 (27), p.19418-19426 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The N protein of phage lambda prevents termination of transcription by Escherichia coli RNA polymerase at Rho-dependent and
-independent terminators in the lambda early operons. The modification of RNA polymerase by N requires an N-utilization (nut)
site, present in each lambda early operon, and involves the E. coli factors NusA, NusB, NusG, and ribosomal protein S10. We
show that, in the presence of NusA, N inhibits pausing by RNA polymerase and Rho-dependent termination in vitro at three sites
in the lambda terminator tR1 which are located less than 100 base pairs downstream from nutR. NusA is also sufficient for
partial antitermination at sites located farther downstream from nutL and nutR if there is a high concentration of N in the
reaction. At low concentrations of N, the additional factors NusB, S10, and NusG are essential for antitermination at distal
sites. In these conditions, the presence of NusA, NusB, S10, and NusG in the reaction enables N-modified RNA polymerase to
elongate efficiently and processively through Rho-dependent and -independent terminators over distances as great as 7 kilobases
downstream from the lambda nut sites. This substantial processivity of antitermination in vitro also occurs in vivo and probably
reflects the stable association of N, NusA, NusB, S10, and NusG with RNA polymerase and nut site RNA in elongation complexes
transcribing the lambda chromosome. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/S0021-9258(18)41792-9 |