Molecular characterization of conventional and new repeat-induced mutants of nit-3, the structural gene that encodes nitrate reductase in Neurospora crassa
| Autor: | Patricia M. Okamoto, George A. Marzluf, Reginald H. Garrett |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Mutant
Nonsense mutation Blotting Western Genes Fungal Molecular Sequence Data Nitrate reductase Neurospora Nitrate Reductase Neurospora crassa Nitrate Reductases Genetics Amino Acid Sequence Genes Suppressor Molecular Biology Gene Alleles Crosses Genetic Repetitive Sequences Nucleic Acid biology Base Sequence Point mutation Structural gene biology.organism_classification Molecular biology Biochemistry Mutation Plasmids |
| Zdroj: | Moleculargeneral genetics : MGG. 238(1-2) |
| ISSN: | 0026-8925 |
| Popis: | Nitrate reductase of Neurospora crassa is a dimeric protein composed of two identical subunits, each possessing three separate domains, with flavin, heme, and molybdenum-containing cofactors. A number of mutants of nit-3, the structural gene that encodes Neurospora nitrate reductase, have been characterized at the molecular level. Amber nonsense mutants of nit-3 were found to possess a truncated protein detected by a specific antibody, whereas Ssu-1-suppressed nonsense mutants showed restoration of the wild-type, full-length nitrate reductase monomer. The mutants show constitutive expression of the truncated nitrate reductase protein; however normal control, which requires nitrate induction, was restored in the suppressed mutant strains. Three conventional nit-3 mutants were isolated by the polymerase chain reaction and sequenced; two of these mutants were due to the deletion of a single base in the coding region for the flavin domain, the third mutant was a nonsense mutation within the amino-terminal molybdenum-containing domain. Homologous recombination was shown to occur when a deleted nit-3 gene was introduced by transformation into a host strain with a single point mutation in the resident nit-3 gene. New, severely damaged, null nit-3 mutants were created by repeat-induced point mutation and demonstrated to be useful as host strains for transformation experiments. |
| Databáze: | OpenAIRE |
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