LINE1

LINE1 (also L1 and LINE-1) are transposable elements in the DNA of some organisms and belong to the group of Long interspersed nuclear elements (LINEs). L1 comprise approximately 17% of the human genome.[1]

The majority of L1 in the human genome are inactive; however, some retained the ability to retrotranspose.[2] Human L1 has been reported to have transferred to the genome of the gonorrhea bacteria.[3]

Structure

A typical L1 element is approximately 6,000 base pairs long and consists of two non-overlapping open reading frames (ORF) which are flanked by UTR and target site duplications.

First ORF

The first ORF encodes a RNA-binding protein of 500 amino acid lengths that weighs 40 kDA. This protein contains a leucine zipper motif and functions as a chaperone.[4]

Trimeric structure and flexibility of the L1ORF1 protein in human L1 retrotransposition.

Second ORF

The second ORF of the L1 encodes a protein-complex that has endonuclease and reverse transcriptase activity. The encoded protein has a molecular weight of 150 kDA.

UTR

The 5' Untranslated region (UTR) of the L1 element contains a strong, internal RNA Polymerase II transcription promoter in sense[5] and a less strong anti-sense promoter.[6]

See also

References

  1. ↑ International Human Genome Sequencing Consortium (Feb 2001). "Initial sequencing and analysis of the human genome". Nature. 409 (6822): 860–921. doi:10.1038/35057062. PMID 11237011.
  2. ↑ Ostertag, Eric M.; Kazazian Jr, Haig H. (December 2001). "Biology of Mammalian L1 Retrotransposons". Annual Review of Genetics. 35 (1): 501–538. doi:10.1146/annurev.genet.35.102401.091032.
  3. ↑ Yong, Ed (2011-02-16). "Gonorrhea has picked up human DNA (and that's just the beginning)". National Geographic. Retrieved 2016-07-14.
  4. ↑ Ewing, A. D.; Ballinger, T. J.; Earl, D.; Harris, C. C.; Ding, L.; Wilson, R. K.; Haussler, D. (2013). "Retrotransposition of gene transcripts leads to structural variation in mammalian genomes". Genome Biology. 14 (3): R22. doi:10.1186/gb-2013-14-3-r22.
  5. ↑ Swergold, G. D. (1990). "Identification, characterization, and cell specificity of a human LINE-1 promoter". Molecular and Cellular Biology. 10 (12): 6718–6729. doi:10.1128/MCB.10.12.6718 (inactive 2015-01-13). PMC 362950Freely accessible. PMID 1701022.
  6. ↑ Mätlik, K; Redik, K; Speek, M (2006). "L1 antisense promoter drives tissue-specific transcription of human genes". Journal of Biomedicine and Biotechnology. 2006 (1): 71753. doi:10.1155/JBB/2006/71753. PMC 1559930Freely accessible. PMID 16877819.
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