Figure 1.

Structure and expression pattern of transgenes. (A) Schematic structure of each transgene that is under the control of the mouse type II collagen α1 chain gene promoter and enhancer and includes an intron and a polyadenylation site. The transgenes contain either β-galactosidase or a dominant-negative RAR (RAR-E) cDNA. (B) The expression pattern of the β-galactosidase transgene was visualized by 5-bromo-4-chloro-3-indolyl β-d-galactoside (X-Gal) staining. Expression was seen in the cartilage primordia of vertebrae, ribs, long bones, exoccipital bone, and the petrous part of the temporal bone in an embryonic day 12.5 (E12.5) embryo.