ABSTRACT
This paper is a review of the data concerning the nature, structural organization, properties and biological significance of the particles, containing mRNA and pre-mRNA (precursor of mRNA), i. e., (1) nuclear pre-mRNA-containing particles (2) free cytoplasmic mRNP (ribonucleoproteins), or informosomes (3) polysome-bound mRNP. Some new data on the comparison of nuclear and cytoplasmic particles, the nature of poly A-containing structures, involvement of informofers in Adenovirusspecific RNA transfer are presented. The general scheme of mRNA transport from nucleus to cytoplasm is discussed.