ISSN:
1617-4623
Keywords:
Ankyrin repeat
;
Neurospora crassa
;
Phosphate metabolism
;
Signal transduction
;
Transcriptional regulation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract In response to phosphorus limitation, the fungusNeurospora crassa synthesizes a number of enzymes that function to bring more phosphate into the cell. The NUC-2 protein appears to sense the availability of phosphate and transmits the signal down-stream to the regulatory pathway. Thenuc-2 + gene has been cloned by its ability to restore growth of anuc-2 mutant under restrictive conditions of high pH and low phosphate concentration. We mapped the cloned gene to the right arm of linkage group II, consistent with the chromosomal position of thenuc-2 mutation as determined by classical genetic mapping. Thenuc-2 + open reading frame is interrupted by five introns and codes for a protein of 1066 amino acid residues. Its predicted amino acid sequence has high similarity to that of its homolog inSaccharomyces cerevisiae, PHO81. Both proteins contain six ankyrin repeats, which have been implicated in the cyclin-dependent kinase inhibitory activity of PHO81. The phenotypes of anuc-2 mutant generated by repeat-induced point mutation and of a strain harboring a UV-inducednuc-2 allele are indistinguishable. Both are unable to grow under the restrictive conditions, a phenotype which is to some degree temperature dependent. Thenuc-2 + gene is transcriptionally regulated. A 15-fold increase in the level of thenuc-2 + transcript occurs in response to a decrease in exogenous phosphate concentration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02173977
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