Construction of mutated mouse model.

<p>(A) Schematic description of transgene construction. A c.3508G>A mutation in Ex50 was generated by PCR-based site-directed mutagenesis and introduced into the targeting vector containing exons form Ex40 to Ex53 of the <i>col2a1</i> gene. A PGK-Neo gene and a PGK-TK gene were also introduced for the positive-negative selection. After being transfected into ES cells, the mutation was transferred into the genome by homologous recombination. The double resistant colonies which were verified with 5′arm+3′arm PCR and sequencing were considered correctly generated and further used for microinjection. (B) Sequencing results of mice of the 3 genotypes. Arrow denotes the c.3508G>A mutation in Ex50. (C) Phenotypes of the neonates of 3 genotypes. Homozygotes were cyanotic immediately after birth and died rapidly; heterozygotes had normal phenotypes.