ABSTRACT
Insect embryos need stores of nutriments to accomplish their development. These are, in part, maternally derived proteins, referred to as vitellins (Vt), that are synthesized in the fat body as high molecular weight precursors called vitellogenins (Vg). Vitellogenins are extensively processed post-translationally by glycosylation, phosphorylation and sulphation prior to their secretion into the maternal blood stream in response to complex hormonal stimuli. During ovarian development, Vg is internalized by the oocyte via receptor mediated endocytosis, and conveyed to endosome like organelles, the yolk granules. Additional protein processing may occur post-endocytically in the oocyte to yield a structurally stable form of Vt suitable for long term storage in the egg.
