YTHDF1 and YTHDC1 m⁶A reader proteins regulate HTLV-1 tax and hbz activity

Area of Science:

• Virology
• Molecular Biology
• Epigenetics

Background:

• Human T-cell leukemia virus type 1 (HTLV-1) causes ATLL and HAM/TSP.
• Viral gene expression regulation is crucial for HTLV-1 persistence and pathogenesis.
• The role of RNA chemical modifications, specifically N6-methyladenosine (m6A), in HTLV-1 biology is largely unknown.

Purpose of the Study:

• To investigate the impact of m6A RNA modifications on HTLV-1 gene expression.
• To identify m6A modification sites on HTLV-1 RNA.
• To determine the role of m6A reader proteins (YTHDF1, YTHDC1) in regulating HTLV-1 transcripts.

Main Methods:

• MeRIP-Seq to map m6A modification sites on HTLV-1 RNA.
• Analysis of viral gene expression in HTLV-1-transformed cells with altered m6A levels.
• Expression vectors and shRNA-mediated knockdown to study reader protein function.
• Assessment of reader protein binding to viral transcripts (Tax and Hbz).

Main Results:

• m6A modifications were identified on HTLV-1 RNA, including Tax and Hbz transcripts.
• Depletion of m6A decreased sense-derived viral genes (Tax, Gag, Env) and increased antisense-derived Hbz.
• YTHDF1 binding decreased sense viral genes and increased Hbz expression, dependent on Tax m6A.
• YTHDC1 influenced both sense and antisense viral transcript abundance and enhanced Tax nuclear export.

Conclusions:

• Global m6A levels and reader proteins YTHDF1 and YTHDC1 are key regulators of HTLV-1 gene expression.
• m6A modification and reader proteins play critical roles in HTLV-1 RNA fate and viral pathogenesis.
• Understanding these RNA modifications offers potential therapeutic targets for HTLV-1-associated diseases.