The beta-geo gene trap was inserted into intron 27. This mutation disrupts the protein kinase D (PKD)-binding domain of all three isoforms while the Rho-GEF domain remains intact. Quantitative PCR analysis of neonatal heart and lung RNA revealed that expression of the E37-38 exon-exon junction is reduced in a dose-dependent manner, while expression of the E4-5 exon-exon junction and the Brx-9 exon-exon junction remains unaffected. (J:231257)