SOS box


SOS box is the region in the promoter of various genes to which the LexA repressor binds to repress the transcription of SOS-induced proteins. This occurs in the absence of DNA damage. In the presence of DNA damage the binding of LexA is inactivated by the RecA activator. SOS boxes differ in DNA sequences and binding affinity towards LexA from organism to organism. Furthermore, SOS boxes may be present in a dual fashion, which indicates that more than one SOS box can be within the same promoter.

Examples

Phylogenetic CladeSequenceReference
Alpha ProteobacteriaGAAC7GAAC
GTTC7GTTC
Betaproteobacteria
Gammaproteobacteria		CTGT8ACAG
DeltaproteobacteriaCTRHAMRYBYGTTCAGS
Gram-positive BacteriaCGAACRNRYGTTYC
CyanobacteriaRGTAC3DGTWCB

See Nucleic acid nomenclature for an explanation of non-GATC nucleotide letters