Definition of multiple, functionally distinct TATA elements, one of which is a target in the hsp70 promoter for E1A regulation.

We have dissected the human hsp70 promoter to define sequence elements allowing response to E1A. Alterations of sequence upstream of the TATA element, either with Bal 31 nuclease or by site-directed mutagenesis, had little or no effect on the response of the promoter to E1A. In general, the basal level was reduced, indicating that these sites interact with factors important for transcription, but regulation persisted. Although a CAT gene driven by just the hsp70 TATA (void of upstream sequences) could be stimulated by E1A, a similar construct containing the early SV40 TATA element was not. Analysis of several additional such constructions indicated that the specific sequence TATAA was crucial. Substitution of the TATAA sequence with the SV40 TATTTAT element in the context of the wild-type hsp70 promoter resulted in loss of E1A inducibility, but maintenance of heat inducibility. Replacement of this element with sequences not related to any TATA element resulted in loss of activity and inducibility. Thus, the SV40 TATA equivalent is functional in the context of the hsp70 promoter but cannot be induced by E1A. We conclude that the target for E1A induction of the hsp70 promoter is TATAA, and that multiple functionally distinct TATA elements, and presumably cognate transcription factors, can be distinguished in eukaryotic cells.