STORED FORMS OF VITELLOGENIN MESSENGER-RNA IN FAT-BODY CELLS OF LOCUSTA-MIGRATORIA

Vitellogenin (Vg), a major yolk protein precursor for locust (Locusta migratoria ia) eggs, is synthesized by female fat body. At the time of oviposition Vg production decreases greatly and Vg mRNA is stored for reinitiation of Vg synthesis in the next reproductive cycle. Sediment ation analysis of fat body extracts and dot-hybridization analysis of RNA have revealed at least three stored forms of Vg mRNA. Two of these sediment in the preribosome zone and one in the postribosome zone. Cs Cl density gradient analysis has revealed that all of them have buoyan t density in the range 1.51-1.57 g/cm(3). In contrast to Vg, synthesis of apolipophorin (apoLp-III) is relatively constant in locust fat bod y. Unlike Vg mRNA, the stored form of ApoLp-III mRNA has density and s edimentation characteristics close to those of stored mRNA forms from other systems. This supports the conclusion that the unusual stored fo rms of Vg mRNA found are not an experimental artifact but have a funct ion in the locust's reproductive cycle.