Identification of L1ASP-derived chimeric transcripts in lung cancer

Long interspersed elements (LINEs or L1 s) are an abundant class of autonomous retrotransposons in the human genome. Full-length L1 elements have two transcriptional regulatory regions: an internal sense promoter and an antisense promoter (ASP). The ASP of L1 elements can generate chimeric RNAs via direct transcription of adjacent genomic sequences. Chimeric transcripts derived from the L1ASP are highly represented, but the extent to which this occurs is largely unknown. Using a genome-wide L1 chimera display (LCD) technique, we have isolated 4 L1 chimeric transcripts (LCTs) in the lung cancer genome. Then, we analyzed the structural characteristics of the 4 LCTs using bioinformatics tool. Expression patterns of the 4 LCTs were analyzed by reverse transcription polymerase chain reaction using normal and lung cancer tissues. LCT24 and LCT25 showed higher expression in lung cancer tissue than in normal tissue. These results suggest that the genome-wide LCD technique could be of great use for further study to find cancer markers via cancer-associated LCTs and to understand cancer biology.