8.30 - Long Interspersed Nuclear Element (LINE-1/L1)
Chapter
Overview
Research
Identity
Additional Document Info
View All
Overview
abstract
Long Interspersed Nuclear Element-1 (Line-1/L1) is the only active autonomous mobile element in the human genome. When activated and mobilized in cis or trans, L1 can induce DNA recombination and breaks, regulate gene structure and function, and influence chromosome organization. These activities have been associated with human disease, genetic variation, genome evolution, and somatic mosaicism, depending on cellular context. Organisms have thus evolved multiple defense mechanisms to restrict L1 expression and retrotransposition, such as transcriptional epigenetic silencing, L1 mRNA deamination and degradation, cytoplasmic sequestration and degradation of L1 mRNAs and proteins, inhibition of target prime insertion, cryptic polyadenation, and non-processive reverse transcription. Consequently, L1 expression is undetectable in most somatic tissues, except for brain and testes. However, reactivation of L1 has been detected in various disease states and upon exposure to various forms of cellular and tissue injury.
