The activation defect of a lambda cI positive control mutant.

The activation defect of a lambda cI positive control mutant. Research Abstract Details 

Research Abstract Table of Contents

Jump to the:

The activation defect of a lambda cI positive control mutant. Abstract Text:

"Positive control" mutants of the cI protein of bacteriophage lambda (lambda cI) bind DNA but, unlike the wild-type protein, fail to activate transcription. According to the original interpretation of Ptashne and co-workers, these mutants bear amino acid substitutions that disrupt a stimulatory interaction between lambda cI bound at operator site O(R)2 and RNA polymerase bound at promoter P(RM), an idea supported by kinetic analysis in one case. Genetic analysis has suggested that one residue in particular, glutamate 34 (E34), is critical for the stimulatory effect of wild-type lambda cI. More recently, however, Kolkhof and Muller-Hill have challenged this view, suggesting that mutant E34K fails to activate because it binds at unusually low concentrations to O(R)3, a site that mediates repression of P(RM). To test this hypothesis, we have examined the behaviour of the lambda cI-E34K mutant both in vitro and in vivo by assaying transcription from P(RM) and monitoring operator site occupancy over a range of protein concentrations. Our results are inconsistent with the interpretation of Kolkhof and Muller-Hill, and demonstrate that under conditions where lambda operator O(R)2 is fully occupied and operator O(R)3 is vacant, wild-type lambda cI activates transcription from promoter P(RM) whereas the mutant does not.

The activation defect of a lambda cI positive control mutant. Publishing Authors By Initials

For similar abstracts research abstracts see: abstracts research

PUBMED ID PMID:

MEDLINE DATE:

The activation defect of a lambda cI positive control mutant. Journal Published:

PUBLICATION TYPE: Research Support, U.S. Gov't,

Journal: Journal of molecular biology

VOLUME: 265

Page Numbers: 261-5

Journal Abbreviation: J. Mol. Biol.

ISSN: 0022-2836

DAY: 24

MONTH: Jan

YEAR: 1997

The activation defect of a lambda cI positive control mutant. Information

Number of References:

LANGUAGE: eng

NlmUniqueID: 2985088

The activation defect of a lambda cI positive control mutant. Keywords Mesh Terms:

KEYWORDS: Viral Regulatory and Accessory Proteins

MESH TERMS: metabolism

Chemical & Substance for Abstract: The activation defect of a lambda cI positive control mutant. Information

Substance Name: Deoxyribonuclease I

Registry Number: EC 3.1.21.1

Grant and Affiliation Information for The activation defect of a lambda cI positive control mutant.

AFFILIATION: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.

Country: ENGLAND

AGENCY: United States NIGMS

GRANT: GM44025

ACRONYM: GM

MEDLINETA: J Mol Biol

REFSOURCE:

DATABASENAME:

ACCESSION NUMBER:

Number Hits: 0

The activation defect of a lambda cI positive control mutant Related Publications

• A sigma-core interaction of the RNA polymerase holoenzyme that enhances promoter escape.
• Activation of prokaryotic transcription through arbitrary protein-protein contacts.
• Amino acid substitutions in the -35 recognition motif of sigma 70 that result in defects in phage lambda repressor-stimulated transcription.
• Anaesthesia for the surgery of pulmonary tuberculosis.
• Analysis of phosphorylation-dependent protein-protein interactions using a bacterial two-hybrid system.
• Detecting cooperative protein-DNA interactions and DNA loop formation by footprinting.
• Gene-specific regulation by a transcript cleavage factor: facilitating promoter escape.
• Specificity determinants for the interaction of lambda repressor and P22 repressor dimers.
• Synergistic activation of transcription by bacteriophage lambda cI protein and E. coli cAMP receptor protein.
• The activation defect of a lambda cI positive control mutant.
• The bacteriophage lambdaQ anti-terminator protein regulates late gene expression as a stable component of the transcription elongation complex.
• Transcriptional activation. How lambda repressor talks to RNA polymerase.