The algT (algU) gene of Pseudomonas aeruginosa, a key regulator involved in alginate biosynthesis, encodes an alternative sigma factor (sigma E).
Chronic infection by alginate-producing (mucoid) Pseudomonas aeruginosa is the leading cause of mortality among cystic fibrosis (CF) patients. During the course of sustained infection, the production of an alginate capsule protects the bacteria and allows them to persist in the CF lung. One of the key regulators of alginate synthesis is the algT (algU) gene encoding a putative alternative sigma factor (sigma E). AlgT was hyperproduced and purified from Escherichia coli. The N-terminal sequence of the purified protein matched perfectly with that predicted from the DNA sequence. The purified protein, in the presence of E. coli RNA polymerase core enzyme, was able to initiate transcription of an algT promoter. Deletion of the -35 region of this promoter abolished this activity in vitro as well as in vivo. These data indicate that the algT gene encodes a sigma factor that is autoregulatory.
Hershberger
C D
CD
Department of Microbiology and Immunology (M/C 790, University of Illinois College of Medicine, Chicago 60612, USA.
Ye
R W
RW
Parsek
M R
MR
Xie
Z D
ZD
Chakrabarty
A M
AM
D000464:Alginates / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D001665:Binding Sites; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D012808:Sigma Factor / Q000096:biosynthesis; D014157:Transcription Factors; D014158:Transcription, Genetic
C079619:AlgU protein, Pseudomonas aeruginosa; D000464:Alginates; D001426:Bacterial Proteins; D006603:Hexuronic Acids; D011994:Recombinant Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C063202:sporulation-specific sigma factors; D020723:Glucuronic Acid; D012321:DNA-Directed RNA Polymerases