A hybrid gene that consists of the Drosophila heat shock gene, hsp70, fused to the E. coli β-galactosidase gene has been introduced into the Drosophila germline by the P element microinjection method. This hybrid includes 194 bp of sequence upstream of the start of the hsp70 transcript. Three strains of transformed flies were isolated and characterized by DNA blotting experiments and by in situ hybridization to polytene chromosomes. Strain Bg61 has a single insert of the hybrid gene at the tip of chromosome 3L, site 61A, and the insert consists of a structure that is consistent with P-element-mediated transposition. Strain Bg9,61 has inserts at both 61A and 9E, while Bg64 has a single insert at 64D. Heat shock induces the formation of a large chromosomal puff at all three sites. These puffs appear and regress with kinetics indistinguishable from the puffing of the heat shock locus, 87C, from which the hsp70 gene, used in these studies, was isolated. The β-galactosidase activity in the transformants is inducible by heat shock and shows a widespread distribution throughout the tissues of larvae and adults.
Bibliographical noteFunding Information:
We thank G. Rubrn and A. Spradling for generously providing information and P-element-containing plasmids prior to publicatron, W. Bender for providing the rosy gene plasmid, and J. Hirsh and W. Bender for a demonstration and for advrce on the microinfection procedure. Also, we thank Lesley Sinclair, D. Berkman, and R. Lobell for assrstance with dechorionations of embryos, and M. Goldberg, Ft. Maclntyre, and V. Vogt for helpful criticisms of the manuscript. This work was supported by National Institutes of Health grant GM25232.
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