The RNA editing enzyme ADAR2 restricts L1 mobility

Loredana Frassinelli, Elisa Orecchini, Sofian Al-Wardat, Marco Tripodi, Carmine Mancone, Margherita Doria, Silvia Galardi, Silvia Anna Ciafrè, Alessandro Michienzi

Research output: Contribution to journalArticlepeer-review


Adenosine deaminases acting on RNA (ADARs) are enzymes that convert adenosines to inosines in double-stranded RNAs (RNA editing A-to-I). ADAR1 and ADAR2 were previously reported as HIV-1 proviral factors. The aim of this study was to investigate the composition of the ADAR2 ribonucleoprotein complex during HIV-1 expression. By using a dual-tag affinity purification procedure in cells expressing HIV-1 followed by mass spectrometry analysis, we identified 10 non-ribosomal ADAR2-interacting factors. A significant fraction of these proteins was previously found associated to the Long INterspersed Element 1 (LINE1 or L1) ribonucleoparticles and to regulate the life cycle of L1 retrotransposons. Considering that we previously demonstrated that ADAR1 is an inhibitor of LINE-1 retrotransposon activity, we investigated whether also ADAR2 played a similar function. To reach this goal, we performed specific cell culture retrotransposition assays in cells overexpressing or ablated for ADAR2. These experiments unveil a novel function of ADAR2 as suppressor of L1 retrotransposition. Furthermore, we showed that ADAR2 binds the basal L1 RNP complex.Overall, these data support the role of ADAR2 as regulator of L1 life cycle.

Original languageEnglish
Pages (from-to)75-87
Number of pages13
JournalRNA Biology
Issue numbersup1
Publication statusPublished - Oct 15 2021


  • Adenosine Deaminase/genetics
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Long Interspersed Nucleotide Elements
  • RNA Editing
  • RNA-Binding Proteins/genetics


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