DROSOPHILA TFIIE - PURIFICATION, CLONING, AND FUNCTIONAL RECONSTITUTION

We present a physical and molecular genetic characterization of Drosop hila melanogaster TFIIE (dTFIIE), a component of the basal RNA polymer ase II transcription apparatus. We have purified dTFIIE to near homoge neity from nuclear extracts of Drosophila embryos and found that it is composed of two subunits with apparent molecular weights of 55 and 38 kDa. Peptide sequence information derived from the two subunits was u sed to isolate the corresponding cDNA clones, revealing that dTFIIE an d human TFIIE share extensive amino acid similarity. Functional conser vation was demonstrated by the ability of bacterially expressed dTFIIE to substitute for human TFIIE in an in vitro transcription assay reco nstituted from purified components. Cytological mapping analysis shows that both subunits are encoded by single copy genes located on chromo some III.