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Mature eggs of the sawfly, Athalia rosae (Hymenoptera: Symphyta: Tenthredinidae), contain two major yolk polypeptides, vitellins (Vn), derived from the corresponding haemolymph precursors, vitellogenins (Vg), (L-Vn and -Vg=180 kDa, and S-Vn and -Vg=50 kDa, on SDSPAGE). A single long polypeptide is translated from a single Vg mRNA (6.5 kb) and is cleaved into two in the female fat body cells, then they are secreted into the haemolymph as Vgs. We examined the antigenic similarity in Vns of 21 species (2 families, 12 genera) of sawflies (Symphyta: Tenthredinoidea) by Western blotting using anti- A. rosae L-Vn and S-Vn antisera. All species had two groups of Vns, L (180–190 kDa) and S (40–65 kDa), in which L reacted only with the anti-L antiserum and S only with the anti-S antiserum. Three species had in addition, a third group of medium-sized Vn, M (100–135 kDa), which had complex reaction profiles. In 14 (2 families, 8 genera) of the 21 species above, we examined the similarity in Vg mRNA nucleotide sequences by Northern blotting using three subclones of the A. rosae Vg cDNA as probes. A single 6.5 kb Vg mRNA was detected under high stringency conditions. |
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