cDNA cloning and expression of a hormone-regulated heat shock protein (hsc 70) from the prothoracic gland of Manduca sexta.
The brain neuropeptide prothoracicotropic hormone (PTTH) stimulates a rapid increase in ecdysteroid hormone synthesis that is accompanied by general and specific increases in protein synthesis, including that of a 70 kDa cognate heat shock protein (hsc 70). To further understand the possible roles of hsc 70, hsc 70 cDNA clones were isolated from a tobacco hornworm (Manduca sexta) prothoracic gland cDNA library. All sequenced clones were highly homologous to the Drosophila hsc 70-4 isoform. Manduca hsc 70 mRNA levels during the last larval instar exhibited a peak at the onset of wandering and a peak that coincided with the major pre-metamorphic peak of ecdysteroid synthesis. Manipulations of the glands' hormonal milieu showed that hsc 70 mRNA levels respond to 20-hydroxyecdysone, dibutyryl cAMP, PTTH and the JH analogue hydroprene. The protein and mRNA data suggest that hsc 70 could be involved in a negative feedback loop regulating assembly of the ecdysone receptor complex.
Rybczynski
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Department of Biology, Coker Hall CB #3280, University of North Carolina at Chapel Hill, NC 27599, Chapel Hill, USA. rybczy@biomass.bio.unc.edu
Gilbert
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004330:Drosophila / Q000235:genetics; D004440:Ecdysone / Q000235:genetics / Q000494:pharmacology*; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics*; D007814:Larva / Q000254:growth & development; D018402:Manduca / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D018978:Molting / Q000502:physiology; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; D018840:HSP70 Heat-Shock Proteins; D004440:Ecdysone