HIV Tat induces a prolonged MYCrelocalization next to IGHin circulating B-cells

With combined antiretroviral therapy (cART), the risk for HIV-infected individuals to develop a non-Hodgkin lymphoma is diminished. However, the incidence of Burkitt lymphoma (BL) remains strikingly elevated. Most BL present a t(8;14) chromosomal translocation which must take place at a time of spatial proximity between the translocation partners. The two partner genes, MYCand IGH, were found colocalized only very rarely in the nuclei of normal peripheral blood B-cells examined using 3D-FISH while circulating B-cells from HIV-infected individuals whose exhibited consistently elevated levels of MYC-IGHcolocalization. In vitro, incubating normal B-cells from healthy donors with a transcriptionally active form of the HIV-encoded Tat protein rapidly activated transcription of the nuclease-encoding RAG1gene. This created DNA damage, including in the MYCgene locus which then moved towards the center of the nucleus where it sustainably colocalized with IGHup to 10-fold more frequently than in controls. In vivo, this could be sufficient to account for the elevated risk of BL-specific chromosomal translocations which would occur following DNA double strand breaks triggered by AID in secondary lymph nodes at the final stage of immunoglobulin gene maturation. New therapeutic attitudes can be envisioned to prevent BL in this high risk group.