Repeated elements represent 45% of the human genome. However, due to their large number and their high sequence homology, the contribution of those elements to the human genome transcriptome remains difficult to study. Particularly, implication of recent LINE-1 (L1) elements to the transcriptional expression profile of cells and tissues is probably under-evaluated. Indeed, those L1 elements possess, in addition to their sense promoter, an antisense promoter (ASP) which allow the transcription of their adjacent sequences (which may include genes) in the form of LINE-1 chimeric transcripts (LCTs). Such LCTs have been already described in literature bur the question remains of the pangenomic extent of this transcriptional activity.
In a study conducted by Catherine Barrière (Pinson, Pogorelcnik et al., 2017), Philippe Arnaud’s team has developed and validated CLIFinder (Chimeric Line Finder), a new software dedicated to the identification of LCTs from stranded paired-end RNA-seq data. Thus, CLIFinder take advantage of the strong potential of next generation sequencing to unravel the complete transcriptome composition and allow the “fishing”, among all the transcriptome’s sequences, of numerous LCTs comprising a L1 sequence and a unique sequence of the genome. The CLIFinder tool is today available for the scientific community to realize extensive analyses in normal and pathological tissues. Indeed, many LCTs have been identified specifically in tumors and are supposed to play a functional role in tumorigenesis.
This software has been published in Bioinformatics (Pinson, Pogorelcnik et al., 2017)