COMPLETE NUCLEOTIDE-SEQUENCE OF THE VITELLOGENIN MESSENGER-RNA FROM THE GYPSY-MOTH - NOVEL ARRANGEMENT OF THE SUBUNIT ENCODING REGIONS

Primary structure analysis and location of introns suggests evolutiona ry relatedness among vitellogenin (Vg) genes from vertebrates and inve rtebrates, including insects. We have determined the complete nucleoti de sequence of the gypsy moth VgmRNA, which shows that its structure i s significantly different from VgmRNAs in other systems. The nucleotid e sequence was determined using overlapping cDNA fragments generated f rom RACE reactions and rTh polymerase-mediated PCR. The VgmRNA is 5579 nucleotides long and codes for both the large and small subunits, How ever, the arrangement of the subunit encoding regions in the gypsy mot h VgmRNA is opposite of what has been observed in other systems, Gypsy moth Vg gene is the first reported example of a Vg gene where the 5'- terminal region codes for the large subunit and the 3'-terminal region for the small subunit, Also, the sequence near the junction of subuni ts was significantly different from those found in other insects. This may. be responsible for the relatively more stable precursor of Vg su bunits found in the gypsy moth hemolymph, It is not clear where this d ivergence in the structure of Vg gene occurred during evolution, since the Vg gene of another lepidopteran, Bombyx mori, conforms to the str ucture of those in vertebrates and other invertebrates.