RESUMO
BTF3 is a protein initially identified in HeLa cells that may be involved in the initiation of transcription. Although its specific role in transcription is unclear, BTF3 can form a stable complex with RNA polymerase II. Recently, BTF3 has also been shown to bind to nascent polypeptide chains. We have cloned a homolog of BTF3 from the fission yeast, Schizosaccharomyces pombe. This homolog, spBTF3, encodes a putative 151 amino acid protein that shares 72% similarity with human BTF3, 73% similarity with the Caenorhabditis elegans homolog and between 52 and 53% similarity with the Saccharomyces cerevisiae homologs, EGD1 and BTT1.
Assuntos
Sequência Conservada/genética , Schizosaccharomyces/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Sequência de Bases , Southern Blotting , Clonagem Molecular , Evolução Molecular , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Genes Fúngicos , Dados de Sequência Molecular , Proteínas Nucleares , Schizosaccharomyces/química , Análise de Sequência , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/químicaRESUMO
The activity of the pH 7.5 NADH-linked nitrate reductase isoform from soybeans is termed inducible. Activity can be observed only in seedlings which have been supplied nitrate. Steady-state levels of mRNA for this isoform also show an absolute requirement for nitrate. Nitrate reductase specific mRNA can be observed within 2 h after nitrate treatment. Levels peaked 48 h after nitrate treatment, while the addition of glutamine to nitrate diminished amounts of nitrate reductase specific mRNA. Using nuclear runoff transcription assays, we have shown that one level of control of nitrate reductase synthesis is transcriptional.
