More active human L1 retrotransposons produce longer insertions

AUTOR(ES)

Farley, Alexander H.

FONTE

Oxford University Press

RESUMO

The vast majority of L1 insertions are 5′ truncated and thus inactive. Yet, the mechanism of 5′ truncation is unknown. To examine whether the frequency of L1 retrotransposition is directly correlated with the length of genomic L1 insertions, we used a cell culture assay to measure retrotransposition frequency and a PCR-based assay to measure L1 insertion length. We tested five full-length human L1 elements that retrotranspose at different frequencies: LRE3, L1RP, L1.3, L1.2A and L1.2B. Our data suggest that L1 insertion length correlates with L1 retrotransposition frequency for insertions >1 kb in length. For two elements, L1RP and L1.2A, we found that swapping the reverse transcriptase domains had little effect. Instead, we found that genomic insertion length and retrotransposition frequency are substantially affected by amino acid substitutions at positions 363, 1220 and 1259 in ORF2. We suggest that the region containing residues 1220 and 1259 may be important in the binding of ORF2p to L1 RNA to facilitate reverse transcription.

Documentos Relacionados

• Two additional potential retrotransposons isolated from a human L1 subfamily that contains an active retrotransposable element.
• The Insertional History of an Active Family of L1 Retrotransposons in Humans
• Molecular archeology of L1 insertions in the human genome
• L1 and HERV-W retrotransposons are hypomethylated in human ovarian carcinomas
• Identifying related L1 retrotransposons by analyzing 3' transduced sequences