Identification of a general transcription factor TFIIAα/β homolog selectively expressed in testis

In this paper we describe the isolation of a cDNA that encodes a human TFIIA alpha/beta-like factor (ALF). The open reading frame of ALF predicts a protein of 478 amino acids that contains characteristic N- and C-terminal conserved domains separated by an internal nonconserved domain, In addition, a rare ALF-containing cDNA, which possesses an extended N terminus (Stoned B/TFIIA alpha/beta-like factor; SALF) has also been identified. The results of Northern and dot blot analyses show that ALF is expressed almost exclusively in testis; in contrast, TFIIA alpha/beta and TFIIA gamma are enriched in testis but are also widely expressed in other human tissues; Recombinant ALF (69 kDa) and TFIITA gamma (12 kDa) polypeptides produced in Escherichia coli form an ALF/gamma complex that can stabilize TBP-TATA interactions in an electrophoretic mobility shift assay. The ALF/gamma complex is also able to restore transcription from the adenovirus major late promoter using HeLa cell nuclear extracts that have been depleted of TFIIA, Overall, the data show that ALF is a functional homolog of human general transcription factor TFIIA alpha/beta that may be uniquely important to testis biology.