SEA-URCHIN HSF ACTIVITY IN-VITRO AND IN TRANSGENIC EMBRYOS

Evidence is provided for the presence at the physiological temperature of 20 degrees C of a heat shock transcriptor factor, HSF, in the nucl ei of P.Iividus embryos. This HSF is able to specifically bind in vitr o the heat shock element, HSE, of the promoter of the hsp70 gene IV, a s suggested by DNA-protein binding reactions and DNAse I protection as says. Upon heat-shock, at the temperature of 31 degrees C, its ability to bind the HSE units becomes much higher. The HSF activated by heat- shock drives in vivo the transcription of the beta-galactosidase repor ter gene in transgenic sea urchin gastrulae. An ATE-like transcription factor, widely described in other organisms but not at all in sea urc hins, is also present in the nuclear extracts and is able to bind the consensus individuated in the hsp70 IV gene promoter. (C) 1997 Academi c Press.