Swt1, a novel yeast protein, functions in transcription.

The conserved TREX complex couples transcription to nuclear mRNA export. Here, we report that the uncharacterized open reading frame YOR166c genetically interacts with TREX complex components and encodes a novel protein named Swt1 for "synthetically lethal with TREX." Co-immunoprecipitation experiments show that Swt1 also interacts with the TREX complex biochemically. Consistent with a potential role in transcription as suggested by its interaction with TREX, Swt1 localizes mainly to the nucleus. Importantly, deletion of Swt1 leads to decreased transcription. Taken together, these data suggest that Swt1 functions in gene expression in conjunction with the TREX complex.