Genetic and morphometric characterization of C/X mice.

(A) RT-PCR on cDNA derived from femoral epiphyseal cartilage from wildtype (Wt) and C/X to detect the full-length form of Xbp1 (Xbp1FL) or the inactive form of Xbp1, lacking exon 2 (Xbp1ΔEx2), and sequencing of cDNA from C/X femoral head cartilage to assay for the deletion of Xbp1 exon 2. (B) PCR for residual loxP site downstream of the p.Asn617Lys Col10a1 coding sequence using genomic DNA derived from Wt and C/X. (C) Alizarin red S/Alcian blue staining of skeletal preparations from newborn, 1 week, and 2 week wildtype (Wt), Xbp1CartΔEx2, ColXN617K and C/X mice. (D-F) Quantification of (D) femoral and (E) tibial length, and (F) intercanthal distance (ICD) from legs from 2 week Wt and mutant mice–Wt, N = 8; Xbp1CartΔEx2, N = 8, ColXN617K, N = 6; C/X, N = 8; statistical analysis performed using Student’s t test.