[Role of general transcription factors and the TFTC complex in transcription activation in vivo as revealed with a model of the hsp70 gene].

General transcription factors (GTFs) were tested for the presence on the promoter of the Drosophila melanogaster hsp70 gene in vivo. TBP, TBP-associated TAF proteins, TFIIB, TFIIF (RAP30), TFIIH (XPB), the TFTC complex (GCN5 and TRRAP), and a Mediator complex subunit (MEDI 3) were detected on the promoter before heat induction. Heat exposure significantly reduced the contents of TBP, TAF proteins, TFIIB, and TFIIF (RAP30), while these proteins were detected in ecdysone-inducible loci. It was assumed on the basis of these findings that a special mechanism induces transcription from the hsp70 promoter and that the apparent presence or absence of GTFs does not always reflect the transcriptional status of a gene.