Two different, adjacent and divergent zinc finger binding sites are necessary for CREA-mediated carbon catabolite repression in the proline gene cluster of Aspergillus nidulans.

Abstract

CREA is the negative regulator mediating carbon catabolism repression in Aspergillus nidulans. We have determined all the sites in the DNA region between the prnD and prnB genes of the proline degradation cluster of this organism which are able to bind a fusion protein containing the zinc finger domain of CREA. The consensus sequence derived for CREA binding is 5′‐SYGGRG‐3′, but not all possible sites derived from this consensus do in fact bind. The binding of at least some sequences of the form 5′‐SYGGAG‐3′ is context dependent. Two different and divergent sites, separated by one base pair (5′‐GCGGAGACCCCAG‐3′), contain the previously sequenced derepressed mutations and are essential for carbon catabolite repression in vivo. We have studied the binding of CREA to the region by DNase I and methylation protection, and by methylation and depurination interference. We propose that this pair of sites is the physiological, cis‐acting element responsible for the carbon catabolite repression of prnB transcription.

Transcriptional Control of Gluconeogenesis in Aspergillus nidulans

“…Overall, the observed pattern of acuG regulation suggests the presence of a significant constitutive level of acuG expression and CreA-mediated carbon catabolite repression. Several putative CreA-binding sites (Cubero and Scazzocchio 1994) are detected in the promoter region with possible strong tandem sites at À805 and À435. In A. oryzae, the expression of the FBP-encoding gene has been shown to be glucose repressed (Nakajima et al 2000).…”

Carbon source regulation of antibiotic production

“…CreA and Cre1 contain two Cys 2 His 2 DNA-binding zinc fingers similar to the Saccharomyces cerevisiae glucose-repressor protein Mig1. 170,179,180 creB encodes a deubiquitinating enzyme, and creC encodes a WD40 protein that contains five WD40 repeats and a proline-rich region. CreC forms a complex with CreB.…”

The gene encoding the major proline transporter of Aspergillus nidulans is upregulated during conidiospore germination and in response to proline induction and amino acid starvation

“…The prnA gene codes for a proline-responsive transcriptional activator, prnX is a proline-inducible gene of unknown function, prnD codes for proline oxidase, prnB for the proline transporter and prnC for ⌬ 1 -pyrroline-5-carboxylate dehydrogenase. prnA, prnX and prnD are transcribed divergently from prnB and prnC and thus there is a region between the prnD and prnB genes which may involve cisacting elements affecting the transcription of both genes (Arst and MacDonald, 1975;Arst et al, 1980;Sharma and Arst, 1985;Sophianopoulou and Scazzocchio, 1989;Gavrias et al, 1994;Sophianopoulou et al, 1993;Cubero and Scazzocchio, 1994).…”