Regulation of LacZ mRNA translatability in a cell-free system at heat shock by the last four sense codons.

Under heat shock conditions translation of Xenopus laevis normal mRNAs in a rabbit reticulocyte cell-free system is blocked whereas hsp70 mRNA is translated. mRNA for E. coli beta-galactosidase containing the last four sense codons of Drosophila hsp70 at its 3'-end was constructed. This mRNA is efficiently translated in a rabbit reticulocyte cell-free system at 43 degrees C.