Transcriptional control of @entity505 source preferences by @entity22760 was assessed with a pobA::lacZ fusion during growth on alternative substrates. The pobA-encoded enzyme catalyzes the first step in the degradation of @entity16366 , a compound consumed rapidly as a sole @entity505 source. If additional aromatic @entity505 sources are available, @entity16366 consumption is inhibited by unknown mechanisms. As reported here, during growth on aromatic substrates, pobA was not expressed despite the presence of @entity16366 , an inducer that normally causes the PobR regulator to activate pobA transcription. Growth on organic acids such as @entity4588 , @entity8516 , and @entity598 allowed higher levels of pobA expression. In each case, pobA expression increased at the end of the exponential growth phase. Complex transcriptional regulation controlled @entity16366 catabolism in multisubstrate environments. Additional studies focused on the wild-type preference for @entity10555 consumption prior to @entity16366 consumption. These compounds are degraded via the @entity6153 and protocatechuate branches of the beta-ketoadipate pathway, respectively. Here, mutants were characterized that degraded @entity10555 and @entity16366 concurrently. These mutants lacked the BenM and CatM transcriptional regulators that normally activate genes for @entity10555 catabolism. A model is presented in which BenM and CatM prevent pobA expression indirectly during growth on @entity10555 . These regulators may affect pobA expression by lowering the PcaK-mediated uptake of @entity16366 . Consistent with this model, BenM and CatM bound in vitro to an operator-promoter fragment controlling the expression of several pca genes, including pcaK. These studies provide the first direct evidence of transcriptional cross-regulation between the distinct but analogous branches of the beta-ketoadipate pathway.

Transcriptional cross-regulation of the @entity6153 and protocatechuate branches of the beta-ketoadipate pathway contributes to XXXX source-dependent expression of the @entity22760 pobA gene.

@entity22760 :: ('62977', 'Species') :: ['Acinetobacter sp. strain ADP1'] @entity8516 :: ('CHEBI:29806', 'Chemical') :: ['fumarate'] @entity4588 :: ('MESH:D019802', 'Chemical') :: ['succinate'] @entity598 :: ('CHEBI:47622', 'Chemical') :: ['acetate'] @entity16366 :: ('MESH:C038193', 'Chemical') :: ['4-hydroxybenzoate'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon'] @entity10555 :: ('MESH:D001565', 'Chemical') :: ['benzoate'] @entity6153 :: ('MESH:C034221', 'Chemical') :: ['catechol']
@entity505 :: (MESH:D002244,Chemical) :: ['carbon']
