Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.10.3.2 (laccase)
 4,656 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of the laccase gene (lacc) of Neurospora crassa is transcriptionally inducible by the protein synthesis inhibitor cycloheximide. A lni-1 mutation, conferring the laccase non-inducible phenotype, was found to be a cpc-1 allele. Northern blots probed with plasmid pLA1, which carries the lacc gene revealed that the cpc-1 mutation abolishes the induced transcription of the lacc gene, indicating requirement of the cpc-1 gene for transcriptional activation of the lacc gene. In Northern blots probed with plasmid pAB1, which bears arg-2 a gene whose transcription is under the control of CPC1, the level of the arg-2 transcript was shown to increase several-fold in wild-type mycelia but remained low in cpc-1 mycelia, after treatment with cycloheximide. This suggests that inhibition of protein synthesis with cycloheximide, as well as amino acid limitation, elicits the CPC1-mediated cross-pathway control. Characterization of the lacc upstream region using a series of 5'-deletion plasmids led to the identification of a 170 bp DNA region required for the induced lacc expression. Sequence analysis of this DNA region demonstrated that it includes a 9 bp sequence with dyad symmetry, ATGAATCAT, which differs only by a central base pair from ATGA(C/G)TCAT, the recognition sequence characteristic of CPC1 and GCN4 binding sites. Possible mechanisms by which CPC1 mediates transcriptional activation of the lacc gene are discussed.
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PMID:Transcriptional activation of a cycloheximide-inducible gene encoding laccase is mediated by cpc-1, the cross-pathway control gene, in Neurospora crassa. 820 46

In Neurospora crassa, expression of the laccase gene is induced by treatment with the protein synthesis inhibitor cycloheximide (CHX). This expression is mediated by CPC1, which acts as a general transcriptional activator when mycelia are treated with CHX or starved for any one of the amino acids. A laccase-derepressed mutant, lah-1, shows pleiotropic deficiencies in growth, hyphal morphology, CHX sensitivity, and production of protoperithecia. Moreover, in the lah-1 mutant, transcript levels of CHX-inducible genes, including lacc, tub-2, tef-1, and amino acid biosynthetic genes such as cpc-1, trp-3, and arg-12, are increased without exposure to CHX. All of the defects exhibited in the lah-1 mutant are suppressed by a mutation in the cpc-1 locus. These findings suggest that the cpc-1 mutation is epistatic to the lah-1 mutation and that the pleiotropic defects in the lah-1 mutant are attributable to constitutive expression of CPCI. These conclusions are supported by a developmental Northern blot analysis of the CHX-inducible genes. Based on these results, the lah-1 gene product appears to regulate expression of the cpc-1 gene negatively. Expression of the CHX-inducible genes was induced by CHX treatment in the lah-1 cpc-1 mutant, as well as in the cpc-1 mutant. This observation indicates that LAH1 is not a component of CHX-responsive pathway itself.
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PMID:Pleiotropic deficiencies of the laccase-derepressed mutant lah-1 are caused by constitutively increased expression of the cross-pathway control gene cpc-1 in Neurospora crassa. 967 Oct 30