Gene targeting strategy for B-hRNASE4 mice. The exon 2 of mouse Rnase4 gene that encodes the full-length protein was replaced by human RNASE4 exon 2 in B-hRNASE4 mice.

Strain specific analysis of RNASE4 mRNA expression in wild-type C57BL/6 mice and B-hRNASE4 mice by RT-PCR. Lung RNA were isolated from wildtype C57BL/6 mice (+/+) and homozygous B-hRNASE4 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human RNASE4 primers. Mouse Rnase4 mRNA was detectable only in wild-type C57BL/6 mice. Human RNASE4 mRNA was detectable only in homozygous B-hRNASE4 mice but not in wild-type mice.

Western blot analysis of RNASE4 protein expression in homozygous B-hRNASE4 mice. Various tissue lysates were collected from C57BL/6N wildtype (+/+) mice and homozygous B-hRNASE4 (H/H) mice, and then analyzed by western blot with anti-RNASE4 antibody. 40 μg total proteins were loaded for western blotting analysis. RNASE4 was detected in bladder.