A peptide of 27 amino acids, VDR(102–76), representing residues 76–102 immediately C-terminal to the second Zn finger of human vitamin D receptor (hVDR) was conjugated to fluorescein-labelled IgG using a bifunctional coupling reagent, m-maleimidobenzoyl n-hydroxysuccinimide. Upon microinjection into the cytoplasm of human osteosarcoma MG-63 cells, the chimeras accumulated in the nuclei. This transport was arrested by chilling or energy depletion. Two other peptides, VDR(80–67), spanning the N-terminal part of VDR(102–76), and VDR(108–97), spanning the C-terminal part of VDR(102–76), were not able to target the linked proteins to the nuclei. SV40(135–112), a peptide containing a well-characterized nuclear localization sequence (amino acids 112–135) of simian virus 40 (SV40) large T-antigen, caused complete nuclear accumulation under the same conditions. Wheat germ agglutinin, which inhibits SV40(135–112) transport, also inhibited the nuclear accumulation of VDR(102–76) as did energy depletion.
vitamin D receptor
VDR(80–67) and VDR(108–97), peptides containing residues 102–76, 80–67 and 108–97, respectively, of VDR
nuclear localization signal
simian virus 40
peptide containing residues 135–112 of SV40 large T-antigen