Col2a1^tm1.1Mcali

Exon 2 was replaced with an exon 2 in which nucleotide substitutions (ACT GCC AGT Ggtcgta to ACG GCC AGT Ggtaagt) resulted in a silent mutation to produce an HaeIII site and mutate the exon IIa 5' splice site. Cre-mediated recombination removed a floxed neo cassette inserted downstream of the modified exon 2. Mice only express isoform IIa. (J:184499)