Retroviral origins of the Caenorhabditis elegans orphan gene F58H7.5.

This work describes the results of the genome-scale analysis of endogenous retrovirus insertions in two C. elegans isolates: the prototype N2 (Bristol) and CB4856 (Hawaii). In total thirteen, identification of potentially replication competent, endogenous retroviral elements is described. Ten elements were identified as conserved between N2 and CB4856 by the reciprocal match of paired LTRs. The description focuses on the particular endogenous retrovirus insertion wich is identified on the proximal arm of the chromosome IV (located at positions IV: 912,948 - 921,658 and IV: 899,767 - 908,485 of the N2 and CB4856 respectively). In both isolates the inserted provirus is flanked by the predicted long terminal repeats (LTR)s of the length of 415 bp and of identical sequence. Provided the absolute LTR sequence identity this particular provirus represents insertion acquired prior to split from the common ancestor, suggesting this insertion event is evolutionary recent. The identified insertion of the endogenous retrovirus embeds the orphan gene F58H7.5, specific to C. elegans lineage. This unprecedented example establishes that in the evolutionary past C. elegans, had acquired the gene of the retroviral origins presumably via mechanisms involving the RNA intermediate.\n\nImportanceThis work describes the retroviral origins of C. elegans orphan gene F58H7.5. Presented work implies that in the evolutionary past the C. elegans have acquired new gene as a result of the infection event. C. elegans is presently regarded as genetic model organism widely used in genetic research. The genome of C. elegans have been sequenced nearly 20 years ago. This unprecedented example establishes that in the evolutionary past C. elegans genome, had acquired the gene of the retroviral origins presumably via mechanisms involving the RNA intermediate.