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.
In Neurospora crassa, the major nitrogen regulatory protein, NIT2, a member of the GATA family of transcription factors, controls positively the expression of numerous genes which specify nitrogen catabolic enzymes. Expression of the highly regulated structural gene nit-3, which encodes nitrate reductase, is dependent upon a synergistic interaction of NIT2 with a pathway-specific control protein, NIT4, a member of the GAL4 family of fungal regulatory factors. The NIT2 and NIT4 proteins both bind at specific recognition elements in the nit-3 promoter, but, in addition, we show that a direct protein-protein interaction between NIT2 and NIT4 is essential for optimal expression of the nit-3 structural gene. Neurospora possesses at least five different GATA factors which control different areas of cellular function, but which have a similar DNA binding specificity. Significantly, only NIT2, of the several Neurospora GATA factors examined, interacts with NIT4. We propose that protein-protein interactions of the individual GATA factors with additional pathway-specific regulatory factors determine each of their specific regulatory functions.
Feng
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B
Department of Biochemistry and Program in Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, Ohio 43210, USA.
Marzluf
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GA
D000595:Amino Acid Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009492:Neurospora crassa / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D009565:Nitrate Reductases / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C068100:NIT2 protein, Neurospora crassa; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C105589:wc-1 protein, Neurospora crassa; C103772:white collar 2 protein, Neurospora; C071240:NIT-4 protein, Neurospora crassa; D009565:Nitrate Reductases