Objective    To detect the interaction between ITGB4BP and P311 by fluorescence resonance energy transfer（FRET）.     Methods    Target fragments P311 and ITGB4BP were subcloned into the DsRed expression vector pDsRed1-N1 and pEGFP-N2

respectively. After the recombinants pP311-DsRed and pITGB4BP-EGFP identified by restriction enzyme digestion and sequencing analysis

the 2 constructs were co-transfected into human embryo kidney 293（HEK293）cells

then the energy transfer efficiency (E) and the molecular distances (R) between P311 and ITGB4BP were detected by FRET through selectively photobleaching the acceptors (P311-DsRed).     Results    Double restriction enzyme digestion showed that the 2 recombinant vectors

  pP311-DsRed and pITGB4BP-EGFP were constructed correctly. Both vectors could express in HEK293 cells

and the fluorescence fusion proteins mainly distributed in the cytoplasm and nuclei and were co-localized. E was equal to 14% and R to 6.3 nm in our experiment.      Conclusion    The recombinant vectors pP311-DsRed and pITGB4BP-EGFP encoding P311-DsRed and ITGB4BP-EGFP distributing in the cytoplasm and nuclei in mammalian cells are constructed successfully

and the interaction between ITGB4BP and P311 can be detected by FRET.