However several bacterial proteins respond to multiple stres

However, several bacterial proteins respond to multiple stressors (heat, salt, oxidation). How can one protein be transcribed and translated in response to multiple stressors, given that each sigma factor produced recognizes its own promoter?

Solution

Stresses are common in order to survive a organism.The immediate response these stresses is critical for survival.Sigma factor is a protein needed only for initiation of RNA synthesis.It enables specific binding of RNA Polymerase to gene promotersSigma factors are proteins regulate transcription in bacteria. Sigma factors activated in response to different environmental conditions.

Using Bacillus licheniformis, a close relative of B. subtilis, have revealed that even though there is conservation of sigma factors, presence or absence of additional transacting proteins makes sigma factor respond differently to the cell envelope stress.

A greater control over wider spectrum of genes could be achieved if the regulator is close to the core of the transcription machinery and it would enable the system to rapidly and simultaneously respond to a number of stresses at the transcriptional level.the sigma factor dissociates from the core polymerase and mRNA synthesis is carried out by the core polymerase. Transcription of a gene can be regulated by the modifi cation of core polymerase subunits, interaction with the regulatory proteins or changes in the regulatory regions of the gene