Isolation of two genes that encode subunits of the yeast transcription factor IIA.

The yeast transcription factor IIA (TFIIA), a component of the basal transcription machinery of RNA polymerase II and implicated in vitro in regulation of basal transcription, is composed of two subunits of 32 and 13.5 kilodaltons. The genes that encode these subunits, termed TOA1 and TOA2, respectively, were cloned. Neither gene shares obvious sequence similarity with the other or with any other previously identified genes. The recombinant factor bound to a TATA binding protein-DNA complex and complemented yeast and mammalian in vitro transcription systems depleted of TFIIA. Both the TOA1 and TOA2 genes are essential for growth of yeast.