Functional Insights into Genic Neighbourhood Organization of Helitron Transposons in Bos taurus Genomes

Transposable elements (TEs) represent well-known factors of genomic variability and evolution. TEs are important providers of regulatory elements that are able to significantly influence the architecture and expression of the host genome. Currently, of a special interest are the DNA transposons helitrons. They are supposed to be involved in horizontal transfer of genetic material between distant taxa and to dramatically impact the host genomes via phenomena of exon-shuffling and gene capture. Thereby, and due to their high level of polymorphism and relatively high frequency in the eukaryotic genomes, helitrons can be used as "anchors" for genome scanning of different breeds of farm animals aimed at revealing their "gene pool standards". Currently, there are no comprehensive studies dedicated to helitrons and their interaction and impact on host genomic landscape in cattle (Bos taurus). Earlier we showed the possibility of using the 3'-end consensus sequence of Heligloria helitrons for estimation of consolidation of different cattle breeds via multilocus genotyping. In the present study, in order to investigate the context features of the DNA regions flanked by the inverted repeats of Heligloria helitrons fragments in Bos taurus genomes, we pyrosequenced such fragments (of about 550 bp in length) from three cattle breeds and analyzed the functional implications of the identified genes. Thus, here we provide an insight into the functional organization of the genic neighbourhood of helitron transposons in the genomes of different Bos taurus breeds and an attempt to understand possible consequences of such distribution of helitrons on these genomes.