INSECT VITELLOGENIN AND VITELLOGENESIS

Insect vitellogenin is the yolk protein precursor synthesized in the fat bodies of matured female insects.After being released into the hemolymph,it is selectively taken up by the developing oocytes.In most insect species investigated,these processes are under the control of the juvenile hormone from the corpora allata.In recent years,insect vitellogenin has been intensively studied not only because it.is closely related to vitellogenesis and reproduction of insects,but also because it provides an excellent experimental model for studying the mechanism of insect hormone action at the molecular level.Studies on insect vitellogenesis and vitellogenin can also give useful information for comparative physiology and molecular evolution by comparing with those in other classes of animals.This paper is a comprehensive review of the current researches on insect vitellogenin and vitellogenesis,dealing with the following problems:(1) site of synthesis of insect vitellogtenin,(2) regulation of vitellogenin synthesis by insect hormone,(3) uptake of vitellogenin by developing oocytes,(4) identification and characterization of insect vitellogenin,(5) effect of various physiological factors on insect vitellogenesis,and (6) fate of yolk protein in insect embryonic development.