▪ Abstract A mechanism for regulating gene expression at the level of transcription utilizes an antagonist of the sigma transcription factor known as the anti-sigma (anti-σ) factor. The cytoplasmic class of anti-σ factors has been well characterized. The class includes AsiA form bacteriophage T4, which inhibits Escherichia coli σ70; FlgM, present in both gram-positive and gram-negative bacteria, which inhibits the flagella sigma factor σ28; SpoIIAB, which inhibits the sporulation-specific sigma factors, σF and σG, of Bacillus subtilis; RbsW of B. subtilis, which inhibits stress response sigma factor σB; and DnaK, a general regulator of the heat shock response, which in bacteria inhibits the heat shock sigma factor σ32. In addition to this class of well-characterized cytoplasmic anti-sigma factors, a new class of homologous, inner-membrane–bound anti-σ factors has recently been discovered in a variety of eubacteria. This new class of anti-σ factors regulates the expression of so-called extracytoplasmic fun...

The anti-sigma factors

Previous work has established that the E. coli htrA gene product is essential for bacterial survival at temperatures above 42 degrees. We have sequenced the htrA gene region and found an open reading frame (ORF) coding for a protein of 491 amino acids with a calculated molecular weight of 51,163 daltons. This molecular weight corresponds well with that seen following electrophoresis on SDS-polyacrylamide gels. This protein has an amino-terminal sequence typical for a leader peptide and undergoes post-translational modification by cleavage of an amino-terminal portion. The insertional mutations which affect the function of the htrA gene map inside this ORF. The levels of htrA mRNA increase rapidly and transiently upon heat shock in a manner independent of the rpoH gene, which encodes the sigma 32 RNA polymerase subunit and is known to regulate transcription of typical heat shock genes. Using S1 mapping and RNA primer extension, we have identified the htrA promoter and found that it is similar to the P3 promoter of the rpoH gene. The P3 promoter is especially active at high temperatures and is recognized by a recently identified transcriptional factor, sigma E.

Sequence analysis and regulation of the htrA gene of Escherichin coli: a σ32-independent mechanism of heat-inducible transcription

The nucleotide sequence of the tetracycline resistance determinant tet(M), located on conjugative transposon Tn916 of Enterococcus faecalis, was determined and found to encode a 72,486-dalton protein exhibiting a high degree of homology with other tet(M) determinants. A short open reading frame corresponding to a 28-amino-acid peptide and containing a number of inverted repeat sequences was noted immediately upstream of tet(M), suggesting that regulation might occur by a mechanism involving transcriptional attenuation. Transcription analyses found this to indeed be the case, showing that the expression of tet(M) resulted from an extension of a small transcript representing the upstream leader region into the resistance determinant. Exposure of cells to tetracycline resulted in a significant increase in the amount of tet(M) transcription; this increase could be explained on the basis of increased transcriptional read-through from the upstream transcript. A model suggesting how transcriptional attenuation might operate in this system is presented.

Characterization of the tet(M) determinant of Tn916: evidence for regulation by transcription attenuation.

Influence of mRNA determinants on translation initiation in Escherichia coli

We have identified a nucleolytic activity in Escherichia coli infected by bacteriophage T4 that introduces cuts in the ribosome binding site of at least two T4 mRNAs Cutting takes place specifically in the GGAG sequences that are complementary to the 3' end of 16S rRNA (Shine-Dalgarno sequence) The nature of this nucleolytic cut has been investigated by reverse transcriptase mapping, anti-mRNA mapping, utilization of the vaccinia virus guanylyltransferase, and labeling by polynucleotide kinase We have compared the sequences of target mRNAs with an mRNA of similar sequence but that is not a substrate for the nuclease This allowed us to narrow down the possibilities for sequence elements that determine nuclease recognition We hypothesize that this nuclease plays a physiological role in the inhibition of expression of a class of phage proteins

A nuclease that cuts specifically in the ribosome binding site of some T4 mRNAs.

Transcriptional activation of bacteriophage T4 middle promoters by the motA protein.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Tracy Modeer

Author Tools

Chat about Author

Papers

Transcriptional activation of bacteriophage T4 middle promoters by the motA protein.