DISTRIBUTION AND ACCUMULATION OF STORAGE PROTEIN-1 IN OVARY OF HYPHANTRIA-CUNEA DRURY

Storage protein-1 (SP-1) is a major storage protein found in the hemol ymph and fat body of Hyphantria cunea. In this study, the uptake and a ccumulation of SP-1 into the ovary of R. cunea was investigated using biochemical and immunocytochemical methods. SP-1 in H. cunea has a hig h methionine content (4.6%) but is not female-specific, like other hig h methionine storage proteins. In the 6-day-old pupal ovary, SP-1 was detectable in trace amounts but accumulated to significant levels towa rd the end of the pupal stage. After adult emergence, SP-1 rapidly dec reased in the ovarian follicles and remained low in the egg. This sugg est that SP-1 is either extensively modified or degraded, causing a lo ss of its antigenic property in the ovary after adult emergence. Durin g vitellogenesis, SP-1 is present in the hemolymph and penetrates thro ugh the tunica propria to reach the perioocytic space. From there, SP- 1 is incorporated into yolk bodies. These results clearly show that SP -1 is taken up by the developing oocyte. Its disappearance suggests th at SP-1 might be an amino acid reservoir for providing precursors for egg formation, in contrast to yolk proteins, which are utilized during postembryonic development. (C) 1998 Wiley-Liss, Inc.