HIV-1 envelope proteins up-regulate N6-methyladenosine levels of cellular RNA independently of viral replication

N-6-methyladenosine (m(6)A) modification of HIV-1 RNA regulates viral replication and protein expression. The m(6)A modification is regulated by two groups of cellular proteins named writers and erasers that add or remove m(6)A, respectively. HIV-1 infection of CD4(+) T-cells increases m(6)A levels of cellular mRNA, but the underlying mechanism is unknown. Here, we show that HIV-1 infection of CD4(+) primary T-cells or Jurkat cells significantly increases m(6)A levels of cellular RNA independently of viral replication. Compared with HIV-1-infected CD4(+) T-cells, similar m(6)A up-regulation was detected in total RNA from HIV-1-infected cells treated with a reverse-transcriptase inhibitor or with heat-inactivated HIV-1. Compared with mock controls, significantly increased m(6)A levels were detected in total RNA from Jurkat cells infected by single-cycle HIV-1 pseudotyped with an HIV-1 envelope (Env) glycoprotein, but not with vesicular stomatitis virus glycoprotein G (VSV-G). Overexpression of HIV-1 Env in HEK293T cells did not affect m(6)A levels of cellular RNA, suggesting that de novo synthesis of Env is not required for m(6)A up-regulation. Interestingly, treatment of Jurkat cells with recombinant gp120 of HIV-1 Env significantly increased m(6)A levels of cellular RNA, which was reduced by a gp120-neutralizing antibody. Preincubation of Jurkat cells with a CD4 receptor-neutralizing antibody blocked HIV-1-induced up-regulation of m(6)A levels in cellular RNA. Moreover, HIV-1 infection or gp120 treatment did not alter the protein expression of m(6)A writers and erasers in cells. Our findings suggest that HIV-1 gp120 binding to the CD4 receptor is required for m(6)A up-regulation in cells.