Figure 4.

Papss2 is regulated by transforming growth factor β. (A) RNA isolated from bovine chondrocytes grown in micromass cultures and either left untreated or treated with 5 ng/transforming growth factor β (TGF-β)/ml for 8 hours (n = 3 separate cows) was used in real-time RT-PCR. Data are shown as tables obtained using REST software [30]. Papss2 and two other selected genes (Prg4 and Plod2) were upregulated after treatment with TGF-β, confirming the microarray results. Gapdh was used as a normalization control. (B) Gene expression was compared by real-time RT-PCR using RNA isolated from 20-week-old wild-type (WT) and dominant-negative TGF-β type II receptor (DNIIR) mice (n = 5 controls and 6 mutants) using REST software. Significant downregulation of Prg4, Papss2 and Plod2 was seen in DNIIR samples. Hprt was used as a normalization control. Fxyd2 was not regulated by TGF-β on the microarray, which we verified by RT-PCR. (C) Cell protein lysates were isolated from articular cartilage of 6-week-old, 20-week-old and 10-month-old control and DNIIR mice (n = 3 each at age 6 weeks, 4 each at age at 20 weeks and 2 each at age 10 months). Papss2 expression was determined by Western blot analysis. Gapdh was used as a loading control. The average Papss2/Gapdh ratios derived from all of the blots are shown, with the ratio for WT set to 1. Papss2 protein was reduced in DNIIR mice at each stage.

Ramaswamy et al. Arthritis Research & Therapy 2012 14:R49   doi:10.1186/ar3762
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