TY - JOUR
T1 - Extensive functional overlap between sigma factors in Escherichia coli
AU - Wade, JT
AU - Roa, DC
AU - Grainger, David
AU - Hurd, D
AU - Busby, Stephen
AU - Struhl, K
AU - Nudler, E
PY - 2006/8/6
Y1 - 2006/8/6
N2 - Bacterial core RNA polymerase (RNAP) must associate with a sigma factor to recognize promoter sequences. Escherichia coli encodes seven sigma factors, each believed to be specific for a largely distinct subset of promoters. Using microarrays representing the entire E. coli genome, we identify 87 in vivo targets of sigma32, the heat-shock sigma factor, and estimate that there are 120-150 sigma32 promoters in total. Unexpectedly, 25% of these sigma32 targets are located within coding regions, suggesting novel regulatory roles for sigma32. The majority of sigma32 promoter targets overlap with those of sigma70, the housekeeping sigma factor. Furthermore, their DNA sequence motifs are often interdigitated, with RNAPsigma70 and RNAPsigma32 initiating transcription in vitro with similar efficiency and from identical positions. SigmaE-regulated promoters also overlap extensively with those for sigma70. These results suggest that extensive functional overlap between sigma factors is an important phenomenon.
AB - Bacterial core RNA polymerase (RNAP) must associate with a sigma factor to recognize promoter sequences. Escherichia coli encodes seven sigma factors, each believed to be specific for a largely distinct subset of promoters. Using microarrays representing the entire E. coli genome, we identify 87 in vivo targets of sigma32, the heat-shock sigma factor, and estimate that there are 120-150 sigma32 promoters in total. Unexpectedly, 25% of these sigma32 targets are located within coding regions, suggesting novel regulatory roles for sigma32. The majority of sigma32 promoter targets overlap with those of sigma70, the housekeeping sigma factor. Furthermore, their DNA sequence motifs are often interdigitated, with RNAPsigma70 and RNAPsigma32 initiating transcription in vitro with similar efficiency and from identical positions. SigmaE-regulated promoters also overlap extensively with those for sigma70. These results suggest that extensive functional overlap between sigma factors is an important phenomenon.
UR - http://www.scopus.com/inward/record.url?scp=33748350078&partnerID=8YFLogxK
U2 - 10.1038/nsmb1130
DO - 10.1038/nsmb1130
M3 - Article
C2 - 16892065
SN - 1545-9985
VL - 13
SP - 806
EP - 814
JO - Nature Structural and Molecular Biology
JF - Nature Structural and Molecular Biology
IS - 9
ER -