RESUMO
StMBF1 (Solanum tuberosum multiprotein bridging factor 1) is a plant member of the MBF1 family of transcriptional co-activators. In an attempt to understand the role of StMBF1, we analyzed its interaction with plant transcription factors of the homeodomain-leucine zipper (Hd-Zip) family, a group of proteins with a typical leucine zipper motif adjacent to a homeodomain. StMBF1 is able to interact in vitro with the Hd-Zip protein Hahb-4 both in the presence and absence of DNA. Upon binding, StMBF1 increases the DNA binding affinity of Hahb-4, and of another plant homeodomain containing protein from the GL2/Hd-Zip IV family, HAHR-1. The biological role of interactions is discussed in this paper.
Assuntos
Proteínas de Homeodomínio/metabolismo , Proteínas de Plantas/metabolismo , Solanum tuberosum/metabolismo , Transativadores/metabolismo , Animais , DNA/metabolismo , Proteínas de Homeodomínio/genética , Humanos , Zíper de Leucina , Proteínas de Plantas/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transativadores/genéticaRESUMO
Coadaptors or coactivators are a new class of transcription factors capable of interconnecting a regulator DNA-binding protein with a component of the basal transcription machinery allowing transcriptional activation to proceed. We report the identification of a novel Solanum tuberosum ssp. tuberosum putative transcription coactivator, named StMBF1 (Solanum tuberosum multiprotein bridging factor 1). The StMBF1 cDNA was isolated from a Fusarium solani f. sp. eumartii-infected potato tuber cDNA library, using a differential screening approach. StMBF1 is up-regulated during fungal attack as well as on wounding. A Fusarium elicitor source and ethylene precursor and salicylic acid also regulate StMBF1 expression. The precise role of StMBF1 during the plant response against environmental stresses remains to be elucidated.