The class II trans-activator CIITA interacts with the TBP-associated factor TAFII32.

AUTOR(ES)

Fontes, J D

RESUMO

The class II trans- activator (CIITA) is the main transcriptional co-activator for the expression of MHC class II proteins. Its N-terminal 125 amino acids function as an independent transcriptional activation domain. Analyses of the primary amino acid sequence of the activation domain predict the presence of three alpha-helices, each with a high proportion of acidic residues. Using site-directed mutagenesis, we found that two of these predicted alpha-helices are required for full transcriptional activation by CIITA. Moreover, a CIITA protein in which both functional alpha-helices have been deleted displays a dominant negative phenotype. This activation domain of CIITA interacts with the 32 kDa subunit of the general transcription complex TFIID, TAFII32. Decreased transcriptional activation by N-terminal deletions of CIITA is correlated directly with their reduced binding to TAFII32. We conclude that interactions between TAFII32 and CIITA are responsible for activation of class II genes.

Documentos Relacionados

• Human Mediator Enhances Activator-Facilitated Recruitment of RNA Polymerase II and Promoter Recognition by TATA-Binding Protein (TBP) Independently of TBP-Associated Factors
• Dual role of the nucleolar transcription factor UBF: trans-activator and antirepressor.
• The yeast TATA-binding protein (TBP) core domain assembles with human TBP-associated factors into a functional TFIID complex.
• TBP-associated factors interact with DNA and govern species specificity of RNA polymerase I transcription.
• Inhibition of Host Transcription by Vesicular Stomatitis Virus Involves a Novel Mechanism That Is Independent of Phosphorylation of TATA-Binding Protein (TBP) or Association of TBP with TBP-Associated Factor Subunits