Intraovarian Synthesis and Tissue Distribution of Hexameric Storage Protein-1 in the Ovary of Red Hairy Caterpillar, Amsacta albistriga.

Abstract: In insects, the source of storage protein-1 (SP1) in ovaries has been the subject of controversy for several decades, and both extraovarian and intraovarian synthesized proteins have been implicated. Ovarian SP1 is presumed to contribute towards the chorion formation. The amino acid analysis of SP-1 of A. albistriga revealed that it consists of relatively high methionine content (10.9%) and is female-specific. The paper deals with the intraovarian synthesis and tissue distribution of SP1 in the pupal ovaries of A. albistriga. Northern hybridization analysis clearly demonstrates that the SP1 gene was expressed in the developing follicles, the maximum accumulation of its transcript at vitellogenic stage (day 4–8) during the mid pupal periods. Further, the result of EM studies regarding the localization of this protein in follicular epithelial cells is confirmed by immunogold labeling tracer techniques. A possible role for ovarian SP1 in A. albistriga and its relationship with SP1 synthesis by the fat body is discussed. [Copyright &y& Elsevier]