Mammary-specific deletion of parathyroid hormone–related protein preserves bone mass during lactation
J. Clin. Invest. Joshua N. VanHouten, et al. 112:1429 doi:10.1172/JCI19504 [
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Figure 1(
a) Ribonuclease protection analysis of PTHrP and cyclophilin transcripts in RNA from yeast (lane 1) and mammary glands from virgin
PTHrPlox/– (lane 2) and
BLG-Cre/PTHrPlox/– (lane 3) mice shows that PTHrP is normally expressed at low levels; therefore significant recombination has not yet taken place. (
b) Ribonuclease protection of PTHrP and cyclophilin in RNA from mammary glands of lactating
BLG-Cre/PTHrPlox/– (lane 2) and
PTHrPlox/– (lane 3) mice. Yeast RNA (lane 1) was a negative control. The efficiency of BLG-Cre–mediated recombination is highlighted by the essentially complete lack of PTHrP RNA in the
BLG-Cre/PTHrPlox/– mammary glands. (
c) PTHrP protein was undetectable (12 of 14) or drastically reduced (2 of 14) in milk from
BLG-Cre/PTHrPlox/– mice (mean 0.06 ± 0.04 nM,
n = 14) compared with littermate
PTHrPlox/– controls (16.4 ± 4.1 nM,
n = 9) as a result of the mammary-specific targeting of
PTHrP gene deletion.
