Fig. 4.

PCBP1 binds to multiple types of nucleic acids. a PCBP1 binds to dsDNA and HIV-1-RT-DNA. HEK293 cells were transfected with the indicated plasmids. Twenty hours later, the cell lysates were incubated with the indicated biotinylated nucleic acids and streptavidin-Sepharose beads for in vitro pull-down assays. The bound proteins were then analyzed by immunoblotting with anti-HA or anti-PCBP1. b PCBP1 binds to dsDNA through its KH1 domain. HEK293 cells were transfected with the indicated plasmids. Twenty hours later, the cells were collected for in vitro pull-down assays as performed in a. c Effects of PCBP1 and its truncations on cGAS-MITA-induced ISRE activation. HEK293 cells (1 × 10⁵) were transfected with ISRE luciferase reporter plasmid (50 ng) and the indicated plasmids for 20 h before luciferase assays were performed. The graph shows the mean ± SEM, n = 3. *P < 0.05, **P < 0.01 (unpaired t-test). d PCBP1 and cGAS, but not MDA5, bind to HSV-1 DNA of the infected cells. HEK293 cells were transfected with HA-tagged PCBP1, cGAS, and MDA5. Twenty hours after transfection, the cells were infected with HSV-1 and incubated for 3 h. Cell lysates were then immunoprecipitated with control IgG or anti-HA. The protein-bound DNAs were extracted and analyzed by qPCR with primers corresponding to the HSV-1 genome. The graph shows the means ± SEM, n = 3. **P < 0.01 (unpaired t-test)