Cooperative action of the nit2 and nit4 transcription factors upon gene expression and the identification of cys-13 gene encoding sulfate permease-I in neurospora crassa /
Year: 2002
Type: article
Abstract: In Neurospora crassa, the nit-3 gene, which encodes nitrate reductase, an enzyme required for the utilization o f inorganic nitrate, is subject to a high degree o f genetic and metabolic regulation as a member o f the nitrogen control circuit.The nit-3 gene promoter contains binding sites for a globally acting protein, NIT2, and a pathwayspecific protein NIT4.Expression o f the nit-3 gene absolutely requires both the NIT2 and NIT4 transcription factors and only occurs under conditions o f nitrogen source derepression and nitrate induction.In the sulfur control circuit, the cys-J4 gene encodes sulfate permease-II that facilitates the assimilation o f sulfate.Expression o f cys-14 is strongly regulated by only a single positive-acting factor CYS3.It was of interest to determine whether NIT2 or NIT4 alone would be capable o f turning on expression o f cys-14 since this structural gene is normally controlled by only one regulatory protein.In this work, NIT2 and/or NIT4 binding elements were introduced into the promoter o f a wildtype cys-14 gene and these constructs were transformed into a cys-13' cys-14~ (rip)mutant strain as well as into nit-2' mutant host.We examined whether any o f the cys-14 genes inserted in these transformants could now be controlled as a nitrogen-regulated gene.Sulfate permease assays revealed that both NIT2 and NIT4 were required for cys-14 expression upon nitrate induction, while neither alone was able to activate any ii
Author: Xiaokui Mo
Institution: The Ohio State University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2883855200