Tnc^tm1Msch

Exon 2 was replaced with a single loxP site by homologous recombination followed by in vitro cre mediated excision. The deleted region encoded the signal peptide and the tenascin assembly domain. While normal transcript was undetected in homozygous mutant mice, weak expression of a transcript in which exon 1 was spliced to exon 3 was identified by Northern blot and RT-PCR analyses. Sequence analysis showed that the aberrant splicing introduced a frameshift mutation. Quantitative immunoblot analysis indicated that protein expression was limited to less than 0.05% of the wild-type level. Immunhistochemical analysis supported this finding. (J:78340)