CHARACTERIZATION OF A HUMAN HOMOLOG OF THE SACCHAROMYCES-CEREVISIAE TRANSCRIPTION FACTOR SPT3 (SUPT3H)

Spt3 is a Saccharomyces cerevisiae transcription factor that is requir ed in vivo for the transcription of a number of RNA polymerase II-tran scribed genes. We report the cloning of the gene encoding the human ho mologue of Spt3, SUPT3H, and its initial functional analysis. The huma n and yeast Spt3 homologues share an overall identity of 30% that defi nes three conserved regions, suggesting possible functional domains. T o determine whether SUPT3H is a true functional Spt3 homologue, we tes ted for complementation of an spt3 Delta mutation in yeast. While expr ession of the full-length SUPT3H is unable to complement an spt3 Delta mutation, expression of a human-yeast chimeric gene that contains 42% human sequences can partially complement an spt3 Delta mutation. Thes e data suggest that the transcriptional control carried out by Spt3 ha s been conserved from yeast to human. (C) 1998 Academic Press.