Sigma factor: Difference between revisions
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== Overview == | == Overview == | ||
'''Sigma (σ) factor''' is the peoptide subunit needed for the initiation of RNA transcription in prokaryotic organisms <scene name='59/591940/Sigma_factor_in_enzyme/1'>as seen here</scene>. As opposed to eukaryotes, who utilize a variety of proteins to initiate gene transcription, prokaryotic transcription is initiated almost completely by a σ-factor. The large and biologically essential protein, RNA polymerase (RNAP), contains one σ-subunit, which binds <scene name='59/591940/Dna_promoter/3'>DNA promoter sequences</scene>, located upstream of transcription start sites. | '''Sigma (σ) factor''' is the peoptide subunit needed for the initiation of RNA transcription in prokaryotic organisms <scene name='59/591940/Sigma_factor_in_enzyme/1'>as seen here</scene>. As opposed to eukaryotes, who utilize a variety of proteins to initiate gene transcription, prokaryotic transcription is initiated almost completely by a σ-factor. The large and biologically essential protein, RNA polymerase (RNAP), contains one σ-subunit, which binds <scene name='59/591940/Dna_promoter/3'>DNA promoter sequences</scene>, located upstream of transcription start sites. <br /> | ||
*'''Sigma factor 70''' or '''RpoD''' is the primary initiation factor during exponential growth. <br /> | |||
*'''Sigma factor 45''' or '''RpoN''' is responsible for the expression of genes involved in Arg catabolism.<br /> | |||
*'''Sigma factor 38''' or '''RpoS''' acts as the master regulator of the general stress response in ''E. coli'' .<br /> | |||
== Function and Structure == | == Function and Structure == | ||
