Figure 1.

Targeting constructs for inactivation of α_i2, α_i3, α_o, and α_q and results of screening by Southern blot analysis. (A) Exon 6 of α_i2 was interrupted with a neomycin (neo) resistance cassette. The predicted change in the BamHI (B) restriction digest pattern (increase in size from 4.0 to 8.0 kb) when probed with the indicated gene fragment (shaded bar) is shown below the gene maps. (B Right) The confirmation on Southern blot. For α_i3, exon 1 was interrupted with a neo cassette and the ATG initiation codon for translation deleted. Southern blot analysis demonstrated the predicted increase in fragment size (from 5.2 to 6.2 kb) with inactivation of the gene. (C) The targeting construct for inactivation of α_o interrupted exon 3 with a neo cassette resulting in a 1.2-kb increase in the BamHI fragment size after homologous recombination. This targeting construct was designed such that both splice variants of α_o would be eliminated. (D) For α_q, exon 6 was interrupted with a neo cassette resulting in a 1.5-kb increase in the XbaI (X) fragment on Southern blot. Endog, endogenous gene; HR, gene after homologous recombination; SKO, single knockout, heterozygous mutant clone.