FIG. 1.

Characterization of the gene trap vector insertion in the dlg locus. (A) Domain structures of wild-type Dlg protein and mutant Dlg protein with the fusion occurring at position 549. Wild-type Dlg contains three PDZ domains and SH3, protein 4.1 binding, and GUK-like domains. (B) Northern blot analysis of brain mRNA extracted from +/+, dlg^gt/+, and dlg^gt/dlg^gt E17.5 embryos for the presence of endogenous dlg and/or dlg-β-geo fusion transcripts. Probes 5′ and 3′ to the vector insertion site were used, as well as a lacZ probe. (C) Western blot analysis of lung lysate from wild-type and dlg^gt/dlg^gt mutant newborn pups using antiserum raised against the N terminus of Dlg. A doublet around 120 to 140 kDa was detected in wild-type lysates which was absent in dlg^gt/dlg^gt mutant mice; however, the expected Dlg–β-Geo fusion protein of 190 kDa was detected. −, untransfected HEK 293 cells; +, HEK 293 cells transfected with full-length murine dlg cDNA.