Rapid DNA cleavage by the LINE-1 endonuclease proximal to DNA ends and at mismatches.

ABSTRACT: Long interspersed element 1 (LINE-1, L1) is a eukaryotic retrotransposon that propagates through an RNA intermediate. Its mutagenic insertion mechanism, target-primed reverse transcription (TPRT), requires coordinated activities of the encoded ORF2 protein (ORF2p) endonuclease (EN) and reverse transcriptase (RT) domains. EN initiates TPRT by nicking target genomic DNA, creating a 3'-OH that primes ORF2p RT for complementary DNA synthesis using the bound L1 RNA template. L1 insertions occur preferentially at 5'-TTTTT↓AA consensus motifs; this bias could reflect site-specific EN cleavage or sequence requirements in the subsequent RT priming step, in which the cut genomic DNA flap must base pair with the poly(A) RNA template. We find that, in vitro, EN is promiscuous, cutting linear DNA oligo

SUBMITTER: Miller BD 

PROVIDER: S-EPMC12809410 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature