Control of extracellular polysaccharide synthesis in Erwinia stewartii and Escherichia coli K-12: a common regulatory function.

AUTOR(ES)

Torres-Cabassa, A

RESUMO

A primary determinant of pathogenicity in Erwinia stewartii is the production of extracellular polysaccharide (EPS). A single mutation can abolish both EPS synthesis and pathogenicity; both properties are restored by a single cosmid clone. Subcloning and insertion analysis have defined a single positive regulatory function which shares a number of similarities with the rcsA function of Escherichia coli K-12, a positive regulator for capsular polysaccharide synthesis. In E. stewartii, the gene promotes the transcription of at least two operons (cps) involved in EPS synthesis; we have previously demonstrated a similar function for rcsA in E. coli. Both genes code for proteins of 25 to 27 kilodaltons; both proteins are unstable in E. coli. The E. stewartii RcsA protein was stabilized in E. coli lon mutants, as the RcsA product from E. coli is. The E. stewartii function complemented E. coli rcsA mutants, and the E. coli RcsA function increased cps expression and restored virulence in E. stewartii mutants. Therefore, these two gram-negative organisms share a similar component of their regulatory circuitry for the control of capsular polysaccharide synthesis.

Documentos Relacionados

• Regulation of capsular polysaccharide synthesis in Escherichia coli K-12: characterization of three regulatory genes.
• REGULATORY MECHANISMS FOR SYNTHESIS OF CAPSULAR POLYSACCHARIDE IN MUCOID MUTANTS OF ESCHERICHIA COLI K12*
• Regulation of argA operon expression in Escherichia coli K-12: cell-free synthesis of beta-galactosidase under argA control.
• Agglutination of Erwinia stewartii Strains with a Corn Agglutinin: Correlation with Extracellular Polysaccharide Production and Pathogenicity
• Regulation of phenylalanine biosynthesis in Escherichia coli K-12: control of transcription of the pheA operon.