Grenson M, Dubois E
Eur J Biochem. 1982 Jan;121(3):643-7. doi: 10.1111/j.1432-1033.1982.tb05834.x.
The npr-1 mutation has two types of effects in Saccharomyces cerevisiae. On one hand, several nitrogen-catabolic enzymes are derepressed in the presence of ammonia, glutamine, or asparagine, which provoke their repression in a wild-type strain. On the other hand, the activity of several ammonia-sensitive permeases is decreased (from 50-100% depending on the permease considered) in npr-1 cells, independently of the nitrogen source used for growth. Our results favour the idea that the primary effect of the npr-1 mutation is on the permeases, and that the derepression of the enzymes is a consequence of the reduced uptake rate of the repressing nitrogen compounds. Hence, the product of the npr-1 gene appears to be directly involved in the development of the activity of a set of permeases which transport nitrogen compounds and which are regulated by nitrogen effectors.
npr - 1突变在酿酒酵母中具有两种类型的效应。一方面，在存在氨、谷氨酰胺或天冬酰胺的情况下，几种氮分解代谢酶会去阻遏，而在野生型菌株中这些物质会引发它们的阻遏。另一方面，在npr - 1细胞中，几种氨敏感通透酶的活性降低（根据所考虑的通透酶，降低幅度为50 - 100%），这与用于生长的氮源无关。我们的结果支持这样一种观点，即npr - 1突变的主要效应在于通透酶，并且酶的去阻遏是抑制性氮化合物摄取速率降低的结果。因此，npr - 1基因的产物似乎直接参与了一组通透酶活性的形成，这些通透酶负责转运氮化合物并受氮效应物调节。
