Translation of Rabbit Globin mRNA

Abstract

IN certain conditions bacterial initiation factors can discriminate between different classes of mRNA, or the individual cistrons of bacteriophage RNA^1–5. Whether messenger specificity is a general phenomenon in eukaryotes as well is controversial, but several reports support the idea that mRNAs can be translated in heterologous systems without the addition of homologous tissue-specific factors, suggesting a lack of specificity^6,10,17. These results have been obtained by adding mRNA either to oocytes⁷ or to crude cell-free systems such as lysates or 30,000g supernatants (S-30). With more fractionated systems—separated ribosomes reconstituted with cell sap—the existence of messenger specific factors is supported^11–13. We have already demonstrated that an S-30 derived from either mouse or rat liver can faithfully translate rabbit globin mRNA without the addition of reticulocyte factors, and now report that fractionation of this S-30 using methods similar to those used by previous workers^11–13 results in a system which will also translate globin mRNA. This fractionated system does not show a requirement for reticulocyte specific factors.