RNA Ligation Precedes U6 snRNA/LINE-1 Retrotransposition

Long Interspersed Element-1 (L1) retrotransposons make up approximately 17% of the human genome. L1 moves throughout the genome via a copy-and-paste mechanism termed retrotransposition. L1 retrotransposition also mobilizes other cellular RNAs such as SINES, U6 snRNA and, mRNA, which for the latter results in the formation of processed pseudogenes. In this study we demonstrate that the RNA ligase RtcB can create chimeric RNAs by joining U6 snRNAs to 5'-truncated L1 or other cellular RNAs. We also show that the retrotransposition of U6/L1 chimeric RNA leads to U6/L1 pseudogene formation. In sum, our data suggests that U6 snRNA and RtcB may have biological roles in addition to their essential functions in mRNA and tRNA splicing, and that the retrotransposition of chimeric RNAs could be a mechanism to create novel genes.]]>