Characterization of a Human Homologue of theSaccharomyces cerevisiaeTranscription Factor Spt3 (SUPT3H)

Abstract

Spt3 is aSaccharomyces cerevisiaetranscription factor that is requiredin vivofor the transcription of a number of RNA polymerase II-transcribed genes. We report the cloning of the gene encoding the human homologue of Spt3, SUPT3H, and its initial functional analysis. The human and yeast Spt3 homologues share an overall identity of 30% that defines three conserved regions, suggesting possible functional domains. To determine whether SUPT3H is a true functional Spt3 homologue, we tested for complementation of anspt3Δmutation in yeast. While expression of the full-lengthSUPT3His unable to complement anspt3Δmutation, expression of a human–yeast chimeric gene that contains 42% human sequences can partially complement anspt3Δmutation. These data suggest that the transcriptional control carried out by Spt3 has been conserved from yeast to human.