Isolation of the Chlamydomonas Regulatory Gene Nit2 by Transposon Tagging
AUTOR(ES)
Schnell, R. A.
RESUMO
Genetic evidence suggests that the NIT2 gene of Chlamydomonas reinhardtii encodes a positive regulator of the nitrate-assimilation pathway. To learn more about the function of the NIT2 gene product, we isolated the gene using a transposon-tagging strategy. A nit2 mutation caused by the insertion of a transposon was identified by testing spontaneous nit2 mutants for the presence of new copies of Gulliver or TOC1, transposable elements that have been identified in Chlamydomonas. In 2 of the 14 different mutants that were analyzed, a Gulliver element was found to be genetically and phenotypically associated with the nit2 mutation. Using the Gulliver element as a probe, one of the transposon-induced nit2 alleles was isolated, and a sequence adjoining the transposon was used to isolate the corresponding wild-type locus. The NIT2 gene was delimited by mapping DNA rearrangements associated with nit2 mutations and mutant rescue by genetic transformation. The NIT2 gene encodes a 6-kb transcript that was not detected in cells grown in the presence of ammonium. Likewise, NIT2-dependent genes are repressed in ammonium-grown cells. These results suggest that repression of the NIT2 gene may mediate metabolite repression of the nitrate assimilation pathway in Chlamydomonas.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1205512Documentos Relacionados
- Interaction between Major Nitrogen Regulatory Protein NIT2 and Pathway-Specific Regulatory Factor NIT4 Is Required for Their Synergistic Activation of Gene Expression in Neurospora crassa
- Recognition of specific nucleotide bases and cooperative DNA binding by the trans-acting nitrogen regulatory protein NIT2 of Neurospora crassa.
- Binding affinity and functional significance of NIT2 and NIT4 binding sites in the promoter of the highly regulated nit-3 gene, which encodes nitrate reductase in Neurospora crassa.
- Complementation of areA- regulatory gene mutations of Aspergillus nidulans by the heterologous regulatory gene nit-2 of Neurospora crassa.
- Characterization of nit-2, the major nitrogen regulatory gene of Neurospora crassa.
