Cultured Aedes albopictus mosquito cells synthesize hormone-inducible proteins.
To provide a framework for biochemical investigation of ecdysteroid action in Aedes albopictus mosquito cells, we examined the effect of 20-hydroxyecdysone on cell growth and morphology, synthesis of inducible proteins (EIPs), and expression of a transfected gene regulated by a synthetic ecdysteroid response element. When cells were cultured in the continuous presence of 10(-6) M 20-hydroxyecdysone, the rate of growth decreased and subtle changes in cell morphology were observed. In both Aedes aegypti and A. albopictus cells, synthesis of a small number of radiolabeled proteins, which appeared as minor bands on sodium dodecyl sulfate-polyacrylamide gels, was induced by treatment with 20-hydroxyecdysone. On two-dimensional polyacrylamide gels, 11 EIPs, ranging in size from approximately 22 to 52 kDa, were identified in A. albopictus C7-10 cells. Ten inducible proteins were localized in the cytoplasmic fraction; EIP28 and EIP31 were detected in both cytoplasmic and nuclear extracts, and EIP29 was detected only in the nucleus, at a very low level. None of these proteins corresponded to small heat shock proteins, whose genes are 20-hydroxyecdysone-inducible in some Drosophila cell lines. The juvenile hormone analog, methoprene, induced expression of a 25 kDa protein in C7-10 cells. Although 20-hydroxyecdysone sustained the synthesis of this methoprene-inducible protein, synthesis did not occur in the presence of 20-hydroxyecdysone alone. In transfected A. albopictus cells, expression of a recombinant DNA construct containing two tandem synthetic ecdysteroid regulatory elements based on a D. melanogaster small heat shock protein gene was modestly induced by 20-hydroxyecdysone.
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Department of Entomology, University of Minnesota, St. Paul 55108.
Gerenday
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Fallon
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D000330:Aedes / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004441:Ecdysterone / Q000502:physiology*; D007525:Isoelectric Focusing; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics
D011506:Proteins; D004441:Ecdysterone