The yeast protein Xtc1 functions as a direct transcriptional repressor.

The yeast protein Xtc1 was identified as a protein that binds directly and specifically to the activation domains of acidic activators such as E2F-1, Gal4 and VP16. Additionally, it was shown to co-purify with the RNA polymerase II holoenzyme complex and it was suggested that Xtc1 functions as a regulator ...
of transcription that modulates the response of RNA polymerase II to transcriptional activators. We have further analyzed the transcription function of Xtc1 and show that its fusion to a heterologous DNA binding domain can repress transcription of a reporter gene in vivo in an Srb10/11-dependent manner. We suggest that the presence of Xtc1 in the RNA polymerase II holoenzyme could help to recruit an Srb10-active form of the holoenzyme to target promoters. This same protein has also been implicated in mitochondrial DNA recombination, maintenance and repair. Determination of the subcellular localization using a GFP-Xtc1 fusion shows that it localizes to both the nucleus and the mitochondria in vivo, which is consistent with Xtc1 having a function in both cellular compartments.
Mesh Terms:
Cell Nucleus, Cyclin-Dependent Kinase 8, Cyclin-Dependent Kinases, Cyclins, Gene Expression Regulation, Fungal, Genes, Reporter, Holoenzymes, Mitochondria, Nuclear Proteins, Promoter Regions, Genetic, Protein Structure, Tertiary, Protein Transport, RNA Polymerase II, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription Factors, Transcription, Genetic
Nucleic Acids Res.
Date: Jun. 01, 2002
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