sigma factor

(noun)

A sigma factor (σ factor) is a protein needed only for initiation of RNA synthesis.

Related Terms

  • RpoS protein
  • oxidative stress

Examples of sigma factor in the following topics:

  • Regulation of Sigma Factor Activity

    • Sigma factors are proteins that function in transcription initiation .
    • The activity of sigma factors within a cell is controlled in numerous ways.
    • However, if transcription of genes is not required, sigma factors will not be active.
    • The anti-sigma factors will bind to the RNA polymerase and prevent its binding to sigma factors present at the promoter site.
    • The anti-sigma factors are responsible for regulating inhibition of transcriptional activity in organisms that require sigma factor for proper transcription initiation.
  • Regulation of Sigma Factor Translation

    • Sigma factor expression is often associated with environmental changes that cause changes in gene expression .
    • Sigma factors include numerous types of factors.
    • The most commonly studied sigma factors are often referred to as a RpoS proteins as the rpoS genes encode for sigma proteins of various sizes.
    • Specifically, the translational control of the sigma factor is a major level of control.
    • The translational control of sigma factors involves the presence and function of small noncoding RNAs.
  • The Heat-Shock Response

    • The up-regulation of HSPs during heat shock is generally controlled by a single transcription factor; in eukaryotes this regulation is performed by heat shock factor (HSF), while σ32 is the heat shock sigma factor in Escherichia coli.
  • Small Regulatory RNAs

    • RPoS genes specifically encode for sigma factors which function as regulators of transcription and stress responses.
  • Repression of Anabolic Pathways

    • Specificity factors alter the specificity of RNA polymerase for a given promoter or set of promoters, making it more or less likely to bind to them (i.e. sigma factors used in prokaryotic transcription).
    • General transcription factors position RNA polymerase at the start of a protein-coding sequence and then release the polymerase to transcribe the mRNA.
  • Endospores

    • These studies have contributed much to our understanding of the regulation of gene expression, transcription factors, and the sigma factor subunits of RNA polymerase.
  • Predisposing Factors

    • The spread and severity of infectious disease is influenced by many predisposing factors.
    • The spread and severity of infectious disease is influenced by many predisposing factors.
    • Genetics is another contributing factor.
    • Overall health is a very important factor in preventing disease.
    • Age is another critical factor.
  • Pathogenicity Islands and Virulence Factors

    • Typical examples of PAIs are adherence factors, toxins, iron uptake systems, invasion factors and secretion systems.
    • Typical examples are adherence factors, toxins, iron uptake systems, invasion factors and secretion systems.
    • PAIs carry genes encoding one or more virulence factors, including, but not limited to, adhesins, toxins, or invasins.
  • Compromised Host

    • Numerous risk factors in the hospital setting can predispose a patient to infection.
    • Numerous risk factors in the hospital setting predispose a patient to infection.
    • These risk factors can broadly be divided into three areas.
    • Patients' treatments can leave them vulnerable to infection: immunosuppression and antacid treatment undermine the body's defences, while antimicrobial therapy (removing competitive flora and only leaving resistant organisms) and recurrent blood transfusions have also been identified as risk factors.
    • Discuss the risk factors that contribute to the acquiring of nosocomial infections or hospital-acquired infections
  • Analytical Epidemiology

    • It is the cornerstone of public health, and informs policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive medicine.
    • Using the case control method, the epidemiologist can look for factors that might have preceded the disease.
    • In this way, other possible factors, e.g., genetic or environmental, might be identified as factors related to the outbreak .
    • The outdated public health advice demonstrates the lack of understanding of the disease and its actual causative factors in the absence of epidemiological analysis.
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