Analysis of involvement of the 3'-untranslated regions in regulating mRNA stability for vitellogenin,cyanoprotein alpha,and cyanoprotein beta from the bean bug,Riptortus clavatus

The degradation of the 3'-untranslated regions (UTRs) of vitellogenin, cyanoprotein alpha, and cyanoprotein beta from the bean bug, Riptortus clavatus, was analyzed in vitro. The degradation pattern was similar for all three RNAs, with a high degradation rate in non-diapausing adult insects and no degradation in the fifth instar nymphs and in diapausing adults, and was not correlated with the expression levels of these three proteins. Proteins binding to the 3'-UTRs were detected in polysomal and cytosolic extracts. These factors, however, were present in all developmental stages. The abundance of the polysomal factor showed little variation, but the cytosolic factor was enriched in adult insects. Cross-competition experiments demonstrated that the same factors bound to all three RNAs with similar affinity. The pattern of degradation, presence of the binding factors in all stages, and their inability to distinguish between the target sequences indicate that the 3'-UTRs do not participate in controlling the expression of these three proteins.     

Vitellogenins and vitellins in the bean bug,Riptortus clavatus (hemiptera: alydidae): Purification,immunological identification,and induction by juvenile hormone

Vitellogenins (Vgs) and vitellins (Vns) were purified from reproductive female adult hemolymph (HL) and newly laid eggs of the bean bug, Riptortus clavatus. They were separated into two (Vg-1 and 2) and three (Vn-1′, Vn-1, and Vn-2) sub-components, respectively, by ion exchange chromatography. Fused rocket immunoelectrophoresis using anti-(Vn-1) serum showed that they are distinguished clearly into two immunologically distinct groups, i.e., Vg-1/Vn-1/Vn-1′ and Vg-2/Vn-2. SDS-PAGE analysis showed Vn-1 (Vn-1′) and Vn-2 have the same and/or smaller subunit component polypeptides as Vg-1 and Vg-2, respectively. Vn-1′ has some lower molecular weight peptides than Vn-1. Quantitative rocket immunoelectrophoretic analysis showed that Vg-1 and Vn-1 (plus V-1′) were detected first on day 3 in the HL and day 4 in the ovary, respectively, after adult emergence, and increased by day 10 in non-diapause female adults. Vg-1 synthesis is induced in diapause female adults in 1 day after the treatment with juvenile hormone (JH) and JH analog (JHA) or in a few days after transfer from short day to long day conditions. © 1996 Wiley-Liss, Inc.     

Isolation and characterization of a larval hemolymph protein in Locusta migratoria

A high-molecular-weight protein, M_r 500,000, has been isolated and characterized from the hemolymph of the migratory locust, Locusta migratoria. It is composed of six seemingly identical subunits of apparent M_r 78,000. It contains low concentrations of carbohydrate and lipid, but high percentages of aspartate and glutamate as well as high proportions of hydrophobic amino acid residues. An antiserum, developed against this purified hemolymph protein, does not react in the double-diffusion test or after immunoblotting with purified lipophorin or cyanoprotein, two other major proteins in locust hemolymph. The concentration of this larval specific protein in the hemolymph of Locusta was examined during the last larval instar and in adult males by quantitative rocket immunoelectrophoresis. Its concentration increases in the second half of the fifth instar, concommitant with an increase in total protein. The protein is detectable by immunological techniques in adults, although its concentration is very low at this stage.     

High-molecular-weight serum proteins from Locusta migratoria: identification of a protein specifically binding juvenile hormone III

ABSTRACT. Tritiated 10,11-epoxyfarnesyl diazoacetate (EFDA), a photoaffinity label, can be covalently attached to the binding site of a JH-III-specific binding protein in the haemolymph of Locusta migratoria migratorioides (R & F). The specificity of the binding of EFDA to the binding protein is verified by displacement with excess unlabelled JH-III, and EFDA can be used to identify the binding protein in native pore-limiting gradient poly(acrylamide) gel electrophoresis (PAGE) and sodium dodecyl sulphate-PAGE. The native binding protein has a molecular weight of 575,000 and is composed of seemingly identical subunits of molecular weight 81,000.
Three other high-molecular weight serum proteins are identified by native PAGE: a lipophorin, composed of two kinds of apolipophorins, a larval storage protein and a cyanoprotein. The molecular weights and subunit structures of these proteins are investigated, but none of these other high-molecular weight proteins bind JH-III to an appreciable extent.