Membrane associated cytoplasmic mRNA in Artemia salina; functional and physical changes during development

The physical and functional properties of the mRNA population from deve-loping embryos of the brine shrimp Artemia salina were characterized. About 20 % of the total poly(A)-rich mRNA in these embryos appears to be specifically associated with the membrane fraction throughout early development, and physi-cally differs markedly from the free cytoplasmic mRNA. The membrane-associated mRNA fraction consists of two well-defined populations of molecular weight of 5.2x10 ^ and 3.6x10)5, whose relative amount changes during the various stages of embryo development. The size of the poly(A) tail at the 3'-end of the mRNA molecules, as estimated by processive phosphorolysis, was found to consist of 180 and 210 adenosine residues for the two respective mRNA species. The in vitro translation products of the membrane-bound mRNA molecules are apparently similar to those of the free mRNA molecules