Correlation of specific coding sequences with specific proteins associated in untranslated cytoplasmic messenger ribonucleoprotein complexes of duck er

Cytoplasmic messenger RNA exists in animal cells in the form of two types of mRNA-protein (mRNP) complexes: in polyribosomes containing the actively translated mRNA, and as free cytoplasmic mRNP with untranslated mRNA.In the case of globin mRNA, these complexes were isolated and purified as a '15 S' particle from polyribosomes and as '20 S' free mRNP; we found that these two different functional forms of globin mRNP contain two extensively different sets of accompanying proteins [ 11.Recently, we could demonstrate that the 20 S globin mRNA is untranslatable in vitro prior to deproteinization whereas, in contrast, the 15 S globin mRNP from polyribosomes is as readily translatable in vitro as the purified 9 S globin mRNA isolated from 20 S or 15 S particles-[2].This