Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As part of a study of transcriptional regulation by viral proteins, we examined whether an acidic region from a regulatory protein of an RNA virus could function as a trans-activator. The NH2-terminal highly acidic domain I of the phosphoprotein (P) of vesicular stomatitis virus (VSV) was fused to the DNA-binding domain of the yeast trans-activator, GAL4. In transient transfection assays, the resulting chimeric protein failed to activate transcription of a reporter CAT gene. However, mutation of basic amino acid residues located at positions 6 and 8 or the alteration of eight amino acids within the acidic domain to eight different amino acids converted the chimeric protein into a transcriptional activator comparable to wild-type GAL4. When subjected to SDS-polyacrylamide gel electrophoresis, the P proteins containing trans-activation-positive mutations in domain I showed an altered mobility, suggesting that these mutations may have caused a conformational change that is critical for trans-activation. Since the acidity of P domain I is not sufficient to activate transcription, additional features of this region must play an important role in GAL4-mediated trans-activation. None of the trans-activation-positive mutants supported VSV RNA transcription in vitro. These results suggest that the amino acid residues within P domain I that can be made to function in the trans-activation of DNA-dependent RNA transcription are distinct from those involved in VSV RNA-dependent RNA transcription.
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PMID:Alteration of specific amino acid residues in the acidic domain I of VSV phosphoprotein (P) converts a GAL4-P(I) hybrid into a transcriptional activator. 165 11

The C1 locus of Zea mays (maize) controls the expression of genes involved in anthocyanin biosynthesis in aleurone and scutellar tissue and encodes a protein with the features of a transcriptional activator. C1-I is a dominant negative mutant which inhibits pigment formation. The structure of the C1-I allele was determined by cloning and sequencing of this allele and of two distinct C1-I derived cDNAs. C1-I has two major and several minor sequence differences with respect to the wild-type C1 allele. Transcription initiation occurs at the same position as in wild-type but transcription yields two different products, one major RNA of 1.3 kb and one minor RNA of 1.45 kb in length, encoding two proteins of 252 and 108 amino acids respectively. The longer 252 amino acid C1-I protein differs from the 273 amino acid wild-type C1 protein at several positions but most prominently at its carboxy terminus, resulting in reduced acidity of the C1-I protein. A similar change in acidity of the Gal4 protein of yeast converted this transcriptional activator into a repressor protein. We discuss the dominant phenotype of C1-I with respect to its possible repressor function in contrast to the activator function of the C1 gene product.
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PMID:Molecular analysis of the C1-I allele from Zea mays: a dominant mutant of the regulatory C1 locus. 230 27

In citrus, the production of anthocyanin pigments requires the activity of the transcriptional activator Ruby. Consequently, loss-of-function mutations in Ruby result in an anthocyaninless phenotype [1]. Several citrus accessions, however, have lost the ability to produce these pigments despite the presence of wild-type Ruby alleles. These specific mutants have captivated the interest of botanists and breeders for centuries because the lack of anthocyanins in young leaves and flowers is also associated with a lack of proanthocyanidins in seeds and, most notably, with an extreme reduction in fruit acidity (involving about a three-unit change in pH). These mutants have been defined collectively as "acidless" [2-4]. We have identified Noemi, which encodes a basic helix-loop-helix (bHLH) transcription factor and which controls these apparently unrelated processes. In accessions of Citron, limetta, sweet lime, lemon, and sweet orange, acidless phenotypes are associated with large deletions or insertions of retrotransposons in the Noemi gene. In two accessions of limetta, a change in the core promoter region of Noemi is associated with reduced expression and increased pH of juice, indicating that Noemi is a major determinant of fruit acidity. The characterization of the Noemi locus in a number of varieties of Citron indicates that one specific mutation is ancient. The presence of this allele in Chinese fingered Citrons and in those used in the Sukkot Jewish ritual [5] illuminates the path of domestication of Citron, the first citrus species to be cultivated in the Mediterranean. This allele has been inherited in Citron-derived hybrids with long histories of cultivation.
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PMID:Noemi Controls Production of Flavonoid Pigments and Fruit Acidity and Illustrates the Domestication Routes of Modern Citrus Varieties. 3089 37