Analysis of the expression of a glucose-regulated protein (GRP78) promoter/CAT fusion gene during early Xenopus laevis development.

Developmental regulation of the expression of a glucose-regulated gene encoding a 78 kd protein, GRP78, has been characterized by microinjection of a rat GRP78/CAT chimeric gene into early Xenopus embryos. Tunicamycin-induced expression of the chimeric gene during Xenopus development was similar to the pattern of endogenous GRP78 protein synthesis, with expression first being detected at gastrula and increasing at least until the tailbud stage. Deletion analysis of the rat GRP78 promoter revealed that sequences between -154 and -130 were necessary for full tunicamycin-inducible and constitutive expression of the fusion gene. These results suggest that there is conservation of regulatory elements of the GRP78 promoter between rat and Xenopus.