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. 2023 Oct 20;14(1):16.
doi: 10.1186/s13100-023-00303-8.

Co-expression of distinct L1 retrotransposon coiled coils can lead to their entanglement

Nikola A Mizgier  1 , Charlie E Jones  1 , Anthony V Furano  2
Affiliations

Co-expression of distinct L1 retrotransposon coiled coils can lead to their entanglement

Nikola A Mizgier et al. Mob DNA. .

Abstract

L1 (LINE1) non-LTR retrotransposons are ubiquitous genomic parasites and the dominant transposable element in humans having generated about 40% of their genomic DNA during their ~ 100 million years (Myr) of activity in primates. L1 replicates in germ line cells and early embryos, causing genetic diversity and defects, but can be active in some somatic stem cells, tumors and during aging. L1 encodes two proteins essential for retrotransposition: ORF2p, a reverse transcriptase that contains an endonuclease domain, and ORF1p, a coiled coil mediated homo trimer, which functions as a nucleic acid chaperone. Both proteins contain highly conserved domains and preferentially bind their encoding transcript to form an L1 ribonucleoprotein (RNP), which mediates retrotransposition. However, the coiled coil has periodically undergone episodes of substantial amino acid replacement to the extent that a given L1 family can concurrently express multiple ORF1s that differ in the sequence of their coiled coils. Here we show that such distinct ORF1p sequences can become entangled forming heterotrimers when co-expressed from separate vectors and speculate on how coiled coil entanglement could affect coiled coil evolution.

Keywords: Coiled coil evolution; Coiled coils; L1 ORF1p; L1 retrotransposon.

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Conflict of interest statement

None of the authors declare a competing interest.

Figures

Fig. 1
Fig. 1
ORF1 structure and coiled coil variants
Fig. 2
Fig. 2
Entanglement of coiled coils that differ at nine positions
Fig. 3
Fig. 3
Entanglement of coiled coils that differ at twenty-one positions
Fig. 4
Fig. 4
Entanglement requires co-expression
See this image and copyright information in PMC

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