Molecular cloning and characterization of a negative-acting nitrogen regulatory gene of Neurospora crassa
โ Scribed by Fu, Ying-Hui ;Young, James L. ;Marzluf, George A.
- Publisher
- Springer
- Year
- 1988
- Tongue
- English
- Weight
- 795 KB
- Volume
- 214
- Category
- Article
- ISSN
- 0026-8925
No coin nor oath required. For personal study only.
โฆ Synopsis
Expression of the structural genes of the nitrogen control circuit of Neurospora crassa is regulated by the positive-acting nit-2 control gene and by the negative-acting nmr control gene. Nitrate reductase is expressed in a constitutive fashion in nmr mutant strains, which appear to be largely insensitive to nitrogen catabolite repression. Thus, nmr mutants are sensitive to chlorate in the presence of ammonia or glutamine, whereas the wild type is chlorate resistant under these conditions. A cosmid library was screened for the presence of the nmr+ gene by the sib selection procedure, and a single cosmid was isolated which transforms the nmr mutant to chlorate resistance at a high frequency. A restriction fragment length polymorphism analysis revealed that the cloned DNA segment maps to the precise genomic location of nmr. Northern blot analyses revealed that the nmr gene is itself not regulated but is expressed constitutively to give a single transcript of approximately 1.8 kb.
๐ SIMILAR VOLUMES
The repeat induced point mutation (RIP) phenomenon has been used to generate new mutants of nmr, the negative nitrogen regulatory gene in Neurospora crassa. The wild-type nmr gene was cotransformed along with the hygromycin B resistance gene into wild-type cells by selecting for hygromycin B resista
A Neurospora crassa library, constructed in a derivative of the plasmid pBR322 (pRK9), was used to transform two E. coli chlD molybdenum cofactor mutants (chlD, chlD: :Mu). Subsequently, one transformant from each of three independent transformation experiments was restriction mapped. All three tran
## Abstract Oocytes are recognized as a source of regulatory molecules that influence follicular development through an array of actions on granulosa cells. Recently, more and more hormones and signaling molecules were identified during follicular developmental processes; however, the details about
Growth of Neurospora crassa on media containing NH4+ leads to the repression of a variety of permeases and alternative pathways which would generate NH4+, so called "ammonium repression." The mutant am2 which lacks NADP-GDH is not subject to ammonium repression of nitrate reductase or urea permease,