A peptide C-terminal to the second Zn finger of human vitamin D receptor is able to specify nuclear localization

Authors


Correspondence to Z. Luo, Department of Biochemistry and Biotechnology, University of Kuopio, P. O. B. 1627, FIN-70211, Kuopio, Finland
Fax: +358 71 2811510.

Abstract

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.

Abbreviations
VDR

vitamin D receptor

VDR(102–76)

VDR(80–67) and VDR(108–97), peptides containing residues 102–76, 80–67 and 108–97, respectively, of VDR

NLS

nuclear localization signal

SV40

simian virus 40

SV40(135–112)

peptide containing residues 135–112 of SV40 large T-antigen

FITC

fluorescein isothiocyanate

h

human

Ancillary