[Molecular organization and genome expression in eukaryotes]

The recent data on the structural organization and expression of genome in eukaryotes are reviewed. Different types of nucleotide sequences (repetitions, palindromes, homopolymers) represented in the regions of genome transcription, as well as in mRNA's of the cytoplasm and nuclear messenger-like RNA's are analyzed. Probable functions of different types of sequences are discussed. The problem of nuclear precursors of cytoplasmic mRNA's and in particular heterogeneous nuclear RNA is considered. It is noted that this population of molecules is heterogeneous not only by the molecular weight, but also by some other parameters. Stable messenger-like 28S and 18S RNA's found in the nuclei are described. In addition to the already known scheme of rapid posttranscriptional processing of pre-mRNA, a hypothesis is put forward to the effect that the selective transport of mRNA molecules stored in the nucleus from the nucleus into the cytoplasm is realized at the expense of extended processing.