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Sigma factor is not released during transcription in Bacillus subtilis
Molecular & General Genetics : MGG
|July 2, 1979
Summary
Bacillus subtilis RNA polymerase uses delta factor for DNA binding and sigma factor for initiating RNA synthesis. These factors act sequentially, with delta released upon DNA binding and sigma remaining bound during transcription.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Bacillus subtilis RNA polymerase requires accessory factors for transcription initiation.
- Sigma (σ) and delta (δ) factors play roles in RNA synthesis.
- Understanding the precise roles of these factors is crucial for deciphering transcription regulation.
Purpose of the Study:
- To elucidate the distinct roles of sigma (σ) and delta (δ) factors in Bacillus subtilis RNA polymerase during transcription initiation.
- To determine the sequential order and release patterns of these factors during the initiation process.
Main Methods:
- Analysis of RNA polymerase core enzyme (E) interactions with DNA in the presence of delta (δ) and sigma (σ) factors.
- Observation of factor release upon formation of enzyme-DNA complexes.
- Assessment of RNA synthesis capability after factor addition.
Main Results:
- Core enzyme with delta factor (Eδ) binds DNA, releasing delta (δ) to form an E-DNA complex.
- Addition of sigma (σ) to the E-DNA complex forms a stable Eσ-DNA complex capable of RNA synthesis.
- Sigma (σ) factor remains bound to the core enzyme throughout RNA synthesis.
Conclusions:
- Delta (δ) factor acts as a DNA recognition factor, facilitating initial DNA binding.
- Sigma (σ) factor functions as an initiation factor, remaining bound for sustained transcription.
- The findings suggest a sequential mechanism for transcription initiation involving distinct roles for delta and sigma factors.