Juvenile hormone regulation of mRNA levels for a highly abundant hemolymph protein in larval Trichoplusia ni

Several hemolymph proteins ranging in size from 73 to 76 kDa increase to very high levels just prior to metamorphosis in Trichoplusia ni (Lepidoptera). One of these proteins (pI = 5.8, Mr = 76,000) was selected for a study of hormonal regulation. The appearance of this protein could be suppressed in vivo by topical treatment with the juvenile hormone analog fenoxycarb. An antiserum for this protein was prepared and shown to react selectively with the 76-kDa protein in whole hemolymph. Translation of poly(A)-containing RNA from untreated larvae yielded the 76-kDa protein, whose identity was verified with the antibody, whereas mRNA from juvenile hormone analog-treated larvae did not. These data indicate that juvenile hormone acts to regulate the level of the mRNA of this hemolymph protein.