Regulation of the ato operon by the atoC gene in Escherichia coli.

AUTOR(ES)

Jenkins, L S

RESUMO

The expression of the Ato enzymes, acetyl coenzyme A:acetoacetyl coenzyme A transferase and thiolase II, is required for growth of Escherichia coli on short-chain fatty acids. The structural genes for these enzymes, atoD, atoA, and atoB, respectively, make up the ato operon. A 48-kilodalton protein encoded by atoC was required for the synthesis or activation of the Ato enzymes. The expression of Ato enzyme activities was inducible in atoC+ strains, constitutive in atoCc strains, and noninducible in atoC mutants. Merodiploid studies demonstrated that the atoCc allele is trans-dominant to the atoC+ allele. To study the action of the trans-acting atoC-encoded activator, the promoter of the ato operon was fused to the promoterless galK gene and introduced into a low-copy-number vector. The resulting low-copy-number fusion plasmid was introduced into atoC+, atoC, and atoCc hosts. The expression of the fused galK gene was inducible in the atoC+ host, noninducible in atoC host strains, and constitutive when harbored in the atoCc host. This indicated that the atoC+ and atoCc gene products act at the level of transcription, stimulating the expression of the ato operon. A working model consistent with these results is presented.

Documentos Relacionados

• The role of bacterial antizyme: From an inhibitory protein to AtoC transcriptional regulator
• Regulation of the Shiga-like toxin II operon in Escherichia coli.
• Positive and negative regulation of the bgl operon in Escherichia coli.
• Operon-specific regulation of ribosomal protein synthesis in Escherichia coli.
• Anaerobic regulation of the hydrogenase 1 (hya) operon of Escherichia coli.