Osteopathy and resistance to vitamin D toxicity in mice null for vitamin D binding protein
J. Clin. Invest. Fayez F. Safadi, et al. 103:239 doi:10.1172/JCI5244 [Go to this article.]

Figure 2
Functional inactivation of the mouse DBP locus by homologous recombination. (a) An autoradiogram of the Northern blot analysis of total RNA from livers of DBP^+/+, DBP^+/–, and DBP^–/– mice hybridized with rat DBP cDNA is shown. The full-length 1.8-kb mDBP mRNA was detected in wild-type mice, present at diminished levels in heterozygous mice, and totally absent in mice homozygous for DBP gene activation. Balanced RNA loading was confirmed by the ethidium bromide staining of 18S rRNA (bottom). (b) Western analysis for serum DBP in 12 mice representing each of the three genotypes is shown. The antibody was a cross-reacting, polyclonal rabbit antiserum to rat DBP. The presence and relative levels of the 58-kDa DBP paralleled the mRNA levels in panel a. (c) Semiquantitative radial immunodiffusion analysis of sera from mice of all three genotypes using the polyclonal antiserum confirmed the absence of DBP in DBP^–/– mice. (d) Serum saturation binding analysis using tracer 25(OH)[³H]D₃ in the presence of increasing concentrations of cold 25(OH)D₃is shown. The data were further analyzed by Scatchard plotting (inset). 25(OH)[³H]D₃, 25(OH)[26,(27)-methyl-³H]vitamin D₃.