The RNA editing enzyme ADAR2 restricts L1 mobility

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• Adenosine deaminases acting on RNA (ADARs) catalyze A-to-I RNA editing.
• ADAR1 and ADAR2 have been implicated as factors in HIV-1 proviral activity.
• The role of ADAR2 in the context of retrotransposons, particularly Long INterspersed Element 1 (LINE1), is not well understood.

Purpose of the Study:

• To investigate the composition of the ADAR2 ribonucleoprotein complex during HIV-1 expression.
• To determine if ADAR2 regulates the life cycle of LINE1 retrotransposons.
• To elucidate the function of ADAR2 in LINE1 retrotransposition.

Main Methods:

• Dual-tag affinity purification coupled with mass spectrometry to identify ADAR2-interacting proteins in HIV-1 expressing cells.
• Cell culture retrotransposition assays to assess the impact of ADAR2 overexpression or ablation on LINE1 activity.
• Analysis of ADAR2 binding to the basal LINE1 ribonucleoprotein (RNP) complex.

Main Results:

• Identified 10 non-ribosomal ADAR2-interacting factors, many associated with LINE1 RNPs.
• Demonstrated that ADAR2 acts as a suppressor of LINE1 retrotransposition.
• Confirmed that ADAR2 binds to the basal LINE1 RNP complex.

Conclusions:

• ADAR2 plays a novel role in suppressing LINE1 retrotransposition.
• ADAR2 is a regulator of the LINE1 retrotransposon life cycle.
• These findings expand the understanding of ADARs' functions beyond RNA editing and viral interactions.