Hgsnat^{Gt(IST11912G1)Tigm}

A selectable marker beta-geo was inserted into the intron 7 of the gene leading to splicing of exon 7 into the beta-geo cassette to generate a fusion protein containing amino acid sequence encoded by exons 17 followed by aminoglycoside 3'-phosphotransferase and -galactosidase. The Btk exon in the trap construct contained termination codons in all reading frames to prevent translation of the downstream exon. Both expression of encoded mRNA measured by real-time quantitative PCR and the level of protein activity measured with fluorogenic substrate Muf--D-glucosaminide in tissues and primary cultures of skin fibroblasts from the homozygous animals were reduced to 0.61.5% of that in control mice. (J:242257)