FIG. 1.

Evidence for a new intermediate transcription factor. In vitro transcription was carried out as previously described (13) for 30 min at 37°C in a total volume of 20 μl with 0.1 μg of uncleaved plasmid (containing the G8R intermediate promoter followed by a template lacking G residues), ribonucleoside triphosphates including [α-³²P]UTP, and additional protein components as indicated in the figure. The RNA was analyzed on a 4% polyacrylamide gel, which was then dried and autoradiographed. Symbols: −, no addition; +, 1× addition; ++, 10× addition. (A) Protein components of the reaction mixture were the 0.15 M NaCl fraction from the second DEAE-cellulose column (0.15 M), a total uninfected HeLa cell extract (HeLa), and the pooled 1 M NaCl fractions from the first and second DEAE-cellulose columns (VITF-X). (B) Protein components were an extract of purified vaccinia virions (VV), a total extract of uninfected HeLa cells (HeLa), and VITF-X purified by DEAE-cellulose, phosphocellulose, SP Sepharose, and single-stranded DNA agarose chromatography.