Optimal heat-induced expression of the Drosophila hsp26 gene requires a promoter sequence containing (CT)n.(GA)n repeats.
We report here the analysis of the sequence requirements for the heat-induced expression of the Drosophila melanogaster hsp26 gene using germline transformation. Heat-induced expression is augmented fivefold by a homopurine/homopyrimidine region from -85 to -134 that is devoid of heat-shock elements but contains numerous (dC-dT).(dG-dA) repeats. Sequences within this interval have been shown to assume a nuclease S1-hypersensitive structure in vitro. In this paper, we extend those in vitro observations, demonstrating that the S1-hypersensitive structure is triple-helical H-DNA formed by a symmetric (dC-dT).(dG-dA) sequence. Thus, the sequences that form H-DNA in vitro are also required in vivo for optimal hsp26 transcription. However, mutational analysis and diethylpyrocarbonate modification experiments in isolated nuclei suggest that the (dC-dT).(dG-dA) sequence does not form H-DNA in vivo and argue against a role for H-DNA in the heat-induced expression of hsp26.
Glaser
R L
RL
Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14851.
Thomas
G H
GH
Siegfried
E
E
Elgin
S C
SC
Lis
J T
JT
D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D004247:DNA / Q000187:drug effects / Q000235:genetics; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D004625:Embryo, Nonmammalian; D005786:Gene Expression Regulation; D005796:Genes; D006360:Heat-Shock Proteins / Q000235:genetics*; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D015345:Oligonucleotide Probes; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012091:Repetitive Sequences, Nucleic Acid
D006360:Heat-Shock Proteins; D015345:Oligonucleotide Probes; D004247:DNA; D004047:Diethyl Pyrocarbonate