Postendocytic Provitellin Processing in the Growing Oocyte of the Short Horned Grasshopper, Oxya japonica japonica (Orthoptera: Acrididae)

초록

Polyclonal antibodies made against 86 kDa (86 k), 80 kDa (80 k) and 54 kDa (54 k)vitellins of Oxya japonica japonica are used for Western blotting. Anti-80 k vitellin antibody iscross-reacted with a 95 kDa (95 k) vitellin. While 95 k vitellin is present both in the femalehemolymph and in the oocyte, 80 k vitellin is detected only in the oocyte and the laid egg. In thegrowing oocytes, as 95 k vitellin is faded out gradually, 80 k vitellin is accumulated increasingly,indicating postendocytic processing of 95 k vitellin brings 80 k vitellin. Further conforming thehypothesis, partial digestion of 95 k vitellin with pepsin and α-chymotrypsin makes severalprotein bands of molecular weight around 80 kDa. Thus, the 95k vitellin may have a cleavage site(s) to produce 80 k vitellin which forms fairly stable tertiary structure. In the reduced condition (20mM glutathion), both 95 k and 80 k vitellins were digested throughly by endogenous proteinase atpH 4. Both 86 k and 54 k vitellins, respectively, show no apparent molecular weight changes in thegrowing oocyte and in the hemolymph.

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