[THE ROLE OF sbr/Dm nxf1 GENE DURING SYNCYTIAL PERIODS OF DEVELOPMENT IN DROSOPHILA MELANOGASTER]

The syncytial development is a feature of early embryogenesis and spermatogenesis in Drosophila melanogaster. All elements of syncytium are interconnected by single cytoskeletal network that enables equal conditions and provides synchronic development. The cytoskeleton is essential for the formation and functioning of the mitotic spindle, cytoskeletal elements are the main structural component of cilia and flagella. Intra- and intercellular transport, morphogenesis processes depend from cytoskeleton on both within a single cell, and at the level of the whole organism. The sbr (small bristles) gene of D. melanogaster belongs to the NXF (nuclear export factor) evolutionarily conservative proteins family. Gene Dm nxf1 (sbr), as well as its orthologs in other organisms, controls the export of poly(A)-containing RNA from the nucleus to the cytoplasm, and the corresponding proteins are usually localized in the nucleus or in the nuclear envelope. For SBR protein we have shown the localization not only in the nucleus, but in the cytoplasm marking of characteristic cytoplasmic structures. A breach of the cytoskeleton in the sbr (Dm nxf1) mutant in D. melanogaster shown by us and cytoplasmic localization of the protein SBR allow us to link the specific functions of this protein with the dynamics of the cytoskeleton.