Runx1t1^tm1Fc

The gene was disrupted by an in-frame insertion of a lacZ-neo cassette into the 3' end of exon 2, which is the common splice acceptor site for several upstream exons. RNase protection assay using a cDNA probe showed the absence the exon 2-4 splice product in brains of homozygous mutants, but an alternative splice product upstream of exon 3 was increased. Western blot of brain extracts from homozygous mutants showed an absence of the 75 kDa and 90 kDa products, presence of the 200 kDa product, and an increase in the 55 kDa product. (J:70590)