Purification of the mRNAs Encoding the Subunits of Larval Serum Proteins 1 and 2 of Drosophila melanogaster

Abstract
The messenger RNA for the 4 subunits of larval serum protein (LSP) 1 and 2 were purified from 3rd instar fat body total RNA by fractionating oligo(dT)-selected RNA on the basis of size. Translations of RNA fractions in vitro showed that the LSP mRNA were free of other fat body messenger activities, but they could not be completely resolved from each other. The MW of the LSP mRNA, estimated from their electrophoretic mobilities in 50% formamide/1.4% agarose gels, ranged from 1.0 .times. 106 to 1.35 .times. 106. These estimates are at least 20% larger than the size the RNA necessary to encode each LSP polypeptide.