Page "Sigma factor" Paragraph 13

* σ < sup > 70 </ sup >( RpoD )-σ < sup > A </ sup >-the " housekeeping " sigma factor or also called as primary sigma factor, transcribes most genes in growing cells.

Every cell has a “ housekeeping ” sigma factor that keeps essential genes and pathways operating.

In the case of E. coli and other gram-negative rod-shaped bacteria, the " housekeeping " sigma factor is σ < sup > 70 </ sup >.

Genes recognized by σ < sup > 70 </ sup > all contain similar promoter consensus sequences consisting of two parts.

Relative to the DNA base corresponding to the start of the RNA transcript, the consensus promoter sequences are characteristically centered at 10 and 35 nucleotides before the start of transcription (– 10 and – 35 ).