Upregulation of a 23 kDa small heat shock protein transcript during pupal diapause in the flesh fly, Sarcophaga, crassipalpis.
A diapause upregulated cDNA clone was isolated from a cDNA library generated from brain mRNA of diapausing Sarcophaga crassipalpis pupae. The clone hybridized to a 1600 bp transcript on a northern blot. The insert is 823 bp in length, has a tentative open reading frame of 615 bp, and codes for a 23 kDa protein. The clone has a high level of identity at the amino acid level with the four small heat shock proteins of Drosophila melanogaster. Northern analysis revealed no detectable expression of the transcript in diapause- or nondiapause-programmed wandering larvae, and only trace expression in nondiapausing pupae. But, the transcript was highly expressed beginning at the onset of diapause and continuing throughout diapause. Expression promptly decreased when diapause was terminated. In nondiapausing individuals the transcript was highly expressed in response to cold shock or heat shock, but temperature stress did not cause greater expression in diapausing pupae. The results imply that expression of this small heat shock protein, a response elicited by temperature stress in nondiapausing individuals, is a normal component of the diapause syndrome. The upregulation of this gene during diapause suggests that it plays an essential role during this overwintering developmental arrest.
Department of Entomology, Ohio State University, Columbus 43210-1220, USA. yocum.1@osu.edu
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Yocum
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Joplin
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Denlinger
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004175:Diptera / Q000235:genetics* / Q000254:growth & development*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D019476:Insect Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011679:Pupa; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D029721:Drosophila Proteins; D006360:Heat-Shock Proteins; C105998:Hsp23 protein, Drosophila; D019476:Insect Proteins