Balbiani bodies in cricket oocytes: Development, ultrastructure, and presence of localized RNAs

Formation of two spherical Balbiani bodies along the long axis of previtell ogenic oocytes in Acheta domesticus was demonstrated by differential interf erence microscopy. The structures form adjacent to and on opposite sides of the germinal vesicle, the anterior body first. Each migrates to the neares t pole of the elongating oocyte and retains its spherical structure until o ccluded from view by accumulating yolk. In situ hybridization, immunocytoch emistry, and confocal immunofluorescent microscopy showed Balbiani body com ponents to include gamma -tubulin, alpha -tubulin, EF1 alpha, and several R NAs homologous to localized Xenopus RNAs implicated in embryonic axis forma tion or germ cell determination. The latter include Xcat2, Xwnt11, Xlsirt, and Xpat. Balbiani body ultrastructure includes a dense cloud of tubular mi tochondria, rough ER, Golgi-like membrane aggregates, and microtubules. The results suggest that molecules and mechanisms specifying early determinati ve events for embryogenesis in vertebrates and insects are highly conserved and that Balbiani bodies may have a role in establishing developmental asy mmetry in the cricket.