Nucleic Acids Research, 1984, Vol. 12, No. 14 5719-5735
© 1984
Articles |
Transcription, export and turnover of Hsp70 and 
ß two Drosophila heat shock genes sharing a 400 nucleotide 5' upstream region
Department of Biology and Molecular Biology Institute, University of California Los Angeles, CA 90024, USA
Received March 8, 1984. Revised July 2, 1984. Accepted July 2, 1984.
A highly homologous 400 nucleotide sequence flanks the 5' end and extends 64 NT into the transcribed portion of all five hsp70 and seven 
ß heat shock genes in Drosophila melanogaster (1–4). To determine the extent to which this sequence dictates coordinate regulation, we compared the total mass, continuous labeling and pulse-labeling of hsp70 and ß RNAs at different times and temperatures of heat shock. By all these measurements, expression of both hsp70 and ß genes increased and decreased in parallel. Hsp70 RNA was generally synthesized at a higher rate and accumlated to a greater extent than ß RNA. As the temperature of heat shock increased, however, the rate of synthesis and accumlation of hsp70 relative to ß RNA decreased. Another difference was that a larger fraction of hap 70, as compared to ß RNA was exported from the nucleus. For both RNAs, export decreased as the heat shock temperature was increased. The hsp70 and ß genes are thus expressed in parallel, but the homologous 5' upstream sequences do not dictate equal rates of transcription or export from the nucleus.