RESUMEN
In this report we describe the isolation and characterization of a gene encoding the transcription factor Acel (Activation protein of cup 1 Expression) in the white rot fungus Phanerochaete chrysosporium. Pc-acel encodes a predicted protein of 633 amino acids containing the copper-fist DNA binding domain typically found in fungal transcription factors such as Acel, Macl and Haal from Saccharomyces cerevisiae. The Pc-acel gene is localized in Scaffold 5, between coordinates 220841 and 222983. A S. cerevisiae acel null mutant strain unable to grow in high-copper medium was fully complemented by transformation with the cDNA of Pc-acel. Moreover, Northern blot hybridization studies indicated that Pc-acel cDNA restores copper inducibility of the yeast cup 1 gene, which encodes the metal-binding protein metallothionein implicated in copper resistance. To our knowledge, this is first report describing an Acel transcription factor in basidiomycetes.
Asunto(s)
Proteínas de Unión al ADN/genética , Proteínas Fúngicas/genética , Phanerochaete/genética , Proteínas de Saccharomyces cerevisiae/genética , Factores de Transcripción/genética , Northern Blotting , Clonación Molecular , Cobre/farmacología , ADN Complementario , Regulación Fúngica de la Expresión Génica , Modelos Genéticos , Phanerochaete/efectos de los fármacos , ARN Mensajero/análisisRESUMEN
The development of an effective hypersensitive response (HR) in any plant system relies, not only in their gene composition and expression, but also on an effective and rapid signal transduction system. Lemon seedlings induce the phenylpropanoid pathway, which results in the de novo biosynthesis of the phytoalexin scoparone, as part of the hypersensitive response against Alternaria alternata. In order to elucidate some of the signaling elements that participate in the development of HR in lemon seedlings, we used several compounds that are known as activators or inhibitors of signal transduction elements in plants or in animal cells. Lemon seedlings treated either with cholera toxin or with phorbol 12-myristate 13-acetate (PMA), in the absence of A. alternata induced phenylalanine ammonia-lyase (PAL, E. C. 4.3.1.5) and the synthesis of scoparone, suggesting the participation of a G-protein and of a serine/threonine kinase, respectively, in signal transduction. The use of trifluoperazine (TFP), W-7, staurosporine, lavendustin A or 2,5dihydroximethyl cinnamate (DHMC) prevented PAL induction as well as scoparone biosynthesis in response to the fungal inoculation, thus allowing us to infer the participation of Calmodulin (CaM), of serine/threonine and of tyrosine protein kinases (TPK) for signal transduction in Citrus limon in response to A. alternata