[Molecular organization of eukaryotic informational RNA].

The review is devoted to the last achievments in the field of the molecular structure of individual eukaryotic mRNAs. The 3'-terminal poly(A) sequence is described as well as the ways of its posttranscriptional addition and degradation. Various suggestions are made concerning the function of poly(A) in mRNAs. The structure of modified and blocked 5'-terminus of mRNA molecule is described in detail. The chemical reactivity of these modified structures (caps) and their sensitivity to enzymatic degradation are characterized as well as the reaction sequence resulting in cap formation and the possible functions of caps in the control of mRNA translation and life time. The primary structure of the 5'- and 3'-untranslated regions and of translated parts of several individual mRNAs is described.