Kaposi Sarcoma Herpesvirus (KSHV) Latency-Associated Nuclear Antigen (LANA) recruits components of the MRN (Mre11-Rad50-NBS1) repair complex to modulate an innate immune signaling pathway and viral latency
Fig 2
KSHV LANA recruits Rad50 and Mre11 in the cytosol.
(A) Co-immunoprecipitation of endogenous LANA, Rad50, Mre11 and Brd4 in BCBL-1 cells upon cytosolic-nuclear fractionation. Cells were lysed and cytoplasmic extracts (Cyto) and nuclear extracts (Nu) were prepared using the Thermo-Fischer Nu-Cyto fractionation kit following the manufacturer‘s instructions. Cytoplasmic and nuclear fractions were incubated overnight with sepharose beads coated with LANA-antibody or IgG-control. Left (INPUT, see Materials and methods): Brd4, Lamin A/C and GAPDH immunoblots were analyzed to confirm the efficiency of the fractionation. Right (IP): immunoprecipitation with LANA-antibody or IgG-control coated-beads and immunoblot for endogenous Rad50, Mre11 and Brd4. (B) Co-immunoprecipitation of endogenous Rad50 and full-length LANA or ΔN mutants (Δ161 and Δ282) transfected into HEK293 cells. HEK293 cells were transfected with LANA constructs (or empty vector). 48 hours later cells were lysed and incubated with benzonase. After centrifugation, cells were incubated overnight with beads coated with LANA-antibody. Left (INPUT): immunoblot to check the expression of LANA constructs and the endogenous Rad50 in the cells. Right (IP from LANA-antibody-coated-beads): immunoblot for endogenous Rad50 co-immunoprecipitation. (C) Co-immunoprecipitation of endogenous LANA and Rad50, Mre11 and CARD9 in latently KSHV-infected THP-1 cells (TrK.219 cells, see Materials and methods). Cells were lysed and incubated with benzonase. After centrifugation, whole cell lysates were incubated overnight with beads coated with anti-LANA or IgG-control antibody. Precipitated complexes were analysed by SDS-PAGE and immunoblotting with the indicated antibodies.