Lamc1^tm1Umr

The genomic region encoding domain III, which contains the nidogen-binding molecule gamma1III4, was deleted and a floxed HSV-TK-neo cassette inserted into the downstream intron via homologous recombination. The HSV-TK-neo cassette was removed by transient expression of cre recombinase in correctly targeted cells. RT-PCR analysis verified the mutant allele in homozygous mutant ES cells. The deletion of gamma1III4 did not appear to interfere with the correct splicing of gamma1III3 to gamma1III5. Ablation of nidogen-binding activity was confirmed in homozygous mutant embryoid bodies via heparin affinity chromatography and rotary shadow electron microscopy. (J:76368)