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Unusual interaction of RNA polymerase with the bacteriophage Mu middle promoter P(m) in the absence of its activator protein Mor
The bacteriophage Mu Mor activator protein is absolutely required for transcription from the Mu middle promoter P(m). However, when RNA polymerase (RNAP) was incubated with P(m) DNA in the absence of Mor, a band at promoter position −51 was hypersensitive to DNase I cleavage, demonstrating an intera...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BlackWell Publishing Ltd
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4287176/ https://www.ncbi.nlm.nih.gov/pubmed/24916637 http://dx.doi.org/10.1002/mbo3.181 |
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author | Mo, Yongkai Howe, Martha M |
author_facet | Mo, Yongkai Howe, Martha M |
author_sort | Mo, Yongkai |
collection | PubMed |
description | The bacteriophage Mu Mor activator protein is absolutely required for transcription from the Mu middle promoter P(m). However, when RNA polymerase (RNAP) was incubated with P(m) DNA in the absence of Mor, a band at promoter position −51 was hypersensitive to DNase I cleavage, demonstrating an interaction of RNAP with the promoter DNA. The hypersensitivity was similar at four different lengths of P(m) DNA assayed from −62 to +10, −62 to +46, −96 to +10, and −96 to +46. The hypersensitivity occurred equally well at 5°C, 15°C, and 30°C, indicating that it did not require open complex formation, which only occurred at 30°C. The −51 hypersensitivity at 5°C and 15°C was eliminated by the addition of heparin, consistent with the possibility that it arose by formation of unstable closed complexes of RNAP bound to P(m) DNA. Generation of the hypersensitive band required the complete RNAP with its αCTDs, but neither the αCTD nor intact α were sufficient for the interaction and resulting hypersensitivity. There was no correlation between the level of hypersensitivity observed in vitro and the level of P(m) activity in vivo, as assayed by the Mor-dependent production of β-galactosidase from a P(m)-lacZ fusion. In an “order of addition” experiment, preincubation of P(m) DNA with Mor followed by addition of RNAP led to the fastest open complex formation, whereas preincubation of P(m) DNA with RNAP gave the slowest. These results support the conclusion that Mor recruits RNAP to P(m) rather than reposition a prebound RNAP, as occurs for C-dependent repositioning of RNAP at the Mu late promoter P(mom). |
format | Online Article Text |
id | pubmed-4287176 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | BlackWell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-42871762015-01-09 Unusual interaction of RNA polymerase with the bacteriophage Mu middle promoter P(m) in the absence of its activator protein Mor Mo, Yongkai Howe, Martha M Microbiologyopen Original Research The bacteriophage Mu Mor activator protein is absolutely required for transcription from the Mu middle promoter P(m). However, when RNA polymerase (RNAP) was incubated with P(m) DNA in the absence of Mor, a band at promoter position −51 was hypersensitive to DNase I cleavage, demonstrating an interaction of RNAP with the promoter DNA. The hypersensitivity was similar at four different lengths of P(m) DNA assayed from −62 to +10, −62 to +46, −96 to +10, and −96 to +46. The hypersensitivity occurred equally well at 5°C, 15°C, and 30°C, indicating that it did not require open complex formation, which only occurred at 30°C. The −51 hypersensitivity at 5°C and 15°C was eliminated by the addition of heparin, consistent with the possibility that it arose by formation of unstable closed complexes of RNAP bound to P(m) DNA. Generation of the hypersensitive band required the complete RNAP with its αCTDs, but neither the αCTD nor intact α were sufficient for the interaction and resulting hypersensitivity. There was no correlation between the level of hypersensitivity observed in vitro and the level of P(m) activity in vivo, as assayed by the Mor-dependent production of β-galactosidase from a P(m)-lacZ fusion. In an “order of addition” experiment, preincubation of P(m) DNA with Mor followed by addition of RNAP led to the fastest open complex formation, whereas preincubation of P(m) DNA with RNAP gave the slowest. These results support the conclusion that Mor recruits RNAP to P(m) rather than reposition a prebound RNAP, as occurs for C-dependent repositioning of RNAP at the Mu late promoter P(mom). BlackWell Publishing Ltd 2014-08 2014-06-10 /pmc/articles/PMC4287176/ /pubmed/24916637 http://dx.doi.org/10.1002/mbo3.181 Text en © 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd. http://creativecommons.org/licenses/by/3.0/ This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Research Mo, Yongkai Howe, Martha M Unusual interaction of RNA polymerase with the bacteriophage Mu middle promoter P(m) in the absence of its activator protein Mor |
title | Unusual interaction of RNA polymerase with the bacteriophage Mu middle promoter P(m) in the absence of its activator protein Mor |
title_full | Unusual interaction of RNA polymerase with the bacteriophage Mu middle promoter P(m) in the absence of its activator protein Mor |
title_fullStr | Unusual interaction of RNA polymerase with the bacteriophage Mu middle promoter P(m) in the absence of its activator protein Mor |
title_full_unstemmed | Unusual interaction of RNA polymerase with the bacteriophage Mu middle promoter P(m) in the absence of its activator protein Mor |
title_short | Unusual interaction of RNA polymerase with the bacteriophage Mu middle promoter P(m) in the absence of its activator protein Mor |
title_sort | unusual interaction of rna polymerase with the bacteriophage mu middle promoter p(m) in the absence of its activator protein mor |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4287176/ https://www.ncbi.nlm.nih.gov/pubmed/24916637 http://dx.doi.org/10.1002/mbo3.181 |
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