Organ-specific transcripts as a source of gene multifunctionality: lessons learned from the Drosophila melanogaster sbr (Dm nxf1) gene

Analysis of the transcriptomes of different organisms has demonstrated that a single gene can have multiple transcripts. The sources of transcriptional variability are the alternative promoters, polyadenylation sites, splicing, and RNA editing. A comparison of the organisms of different taxa has demonstrated that the complexity of organization during evolution arises not due to an increase in the number of protein-coding genes. The greatest variability of transcripts is specific to the nervous and germinal systems. A variety of mechanisms providing for the complexity of the transcriptome ensures a precise and coordinated regulation of organ-specific functions through a combination of cis-acting elements and trans-acting factors. The D. melanogaster sbr (Dm nxf1) gene has proven to be an excellent model for investigating mechanisms potentially leading to the emergence of multiple products with various functions.