The Erwinia chrysanthemi pecT gene regulates pectinase gene expression.
A new type of Erwinia chrysanthemi mutant displaying a derepressed synthesis of pectate lyase was isolated. The gene mutated in these strains, pecT, encodes a 316-amino-acid protein with a size of 34,761 Da that belongs to the LysR family of transcriptional activators and presents 61% identity with the E. coli protein LrhA. PecT represses the expression of pectate lyase genes pelC, pelD, pelE, pelL, and kdgC, activates pelB, and has no effect on the expression of pelA or the pectin methylesterase genes pemA and pemB. PecT activiates its own expression. The mechanism by which PecT regulates pectate lyase synthesis is independent of that of the two characterized regulators of pectate lyase genes, KdgR and PecS. In contrast to most of the members of the LysR family, pecT is not transcribed in a direction opposite that of a gene that it regulates. pecT mutants are mucoid when grown on minimal medium plates and flocculate when grown in liquid minimal medium, unless leucine or alanine is added to the medium. Thus, pecT may regulate other functions in the bacterium.
Surgey
N
N
Laboratoire de Génétique Moléculaire des Microorganismes, Unité Recherche Associée, Villeurbanne, France.
Robert-Baudouy
J
J
Condemine
G
G
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D016974:Dickeya chrysanthemi / Q000201:enzymology / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D011096:Polygalacturonase / Q000096:biosynthesis*; D011133:Polysaccharide-Lyases / Q000096:biosynthesis*; D012097:Repressor Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors
D001426:Bacterial Proteins; C098628:KdgR protein, Erwinia chrysanthemi; C098627:PecT protein, Erwinia chrysanthemi; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C088080:pecS protein, Erwinia chrysanthemi; D011096:Polygalacturonase; D011133:Polysaccharide-Lyases; C023911:pectate lyase