Fig. 1
a Interaction between host cellular proteins and HIV-1 IN was detected by pull down assay. Elution lane consists of protein obtained during washing. Interacted proteins bound to the bead was shown in lane bead b Cellular SFPQ/PSF fragmentation pattern of peptide FAQHGTFEYEYSQR. The ‘b” and “y” ion series derived from the amide bond cleavage during collision induced dissociation of the peptide provide amino acid sequence information. c The interaction between IN and PSF was confirmed by western blot after performing pull down assay of IN with HeLa cell nuclear protein. The proteins were detected with anti-IN and anti-PSF antibody. d Co-immunoprecipitation of mRFP-tagged IN with PSF/SFPQ from nuclear extracts: mRFP-integrase was transfected in HeLa cell line. The cell lysate was then incubated with anti-IN antibody and protein A agarose beads for 4–5 h at 4 °C. The eluted fractions were detected by PSF and IN antibody. Lane bead consists of interacting proteins bound to the bead. Cell lysate consists of only cellular protein with Ni–NTA beads before transfection. e Purified protein–protein interaction detected by western blot. The lanes consists of beads bound to the purified protein was checked for interaction with both IN and PSF in Lanes: PSF + bead—consists of PSF bound to Ni–NTA bead, lane IN + bead—Unbound IN protein to Ni–NTA bead. IN + PSF + bead lane is His-PSF and IN interaction obtained after washing in a Ni+2-NTA affinity bead