These mutant mice possess a loxP-STOP-loxP cassette that disrupts Pkhd1 gene expression resulting in progressive polycystic liver disease. Removal of the cassette with Cre recombinase generates phenotypically normal mice. These mice can be used as a model for autosomal recessive polycystic kidney disease and to track the processing and secretion of fibrocystin.
Christopher J Ward, University of Kansas Medical Center
The PKHD1 (polycystic kidney and hepatic disease 1) gene or fibrocystin, is a large type I membrane protein associated with human autosomal recessive polycystic kidney disease (ARPKD). Pkhd1 is highly expressed in the kidney; the protein undergoes processing and is secreted by exosome-like vesicles (ELV) in the bile and urine. Pkhd1LSL mutant mice possess a loxP-STOP-loxP (LSL) cassette inserted into intron 2 and two SV5-Pk epitope tags placed in-frame into exon 3. The LSL cassette terminates all transcripts in intron 2, generating a null allele. Mice that are homozygous for Pkhd1LSL exhibit progressive polycystic liver disease and liver fibrosis visible by histology at one month of age. Females, but not males, develop proximal tubule dilation and cysts in the kidneys.
When crossed to mice carrying Tg(Gdf9-cre)5092Coo (Stock No. 011062), the LSL cassette is removed, the Pkhd1 gene reactivates, and the expressed protein carries two SV5-Pk epitope tags located in the N-terminus of the protein following cleavage of the signal peptide. Mice homozygous for Pkhd1tm2.1Cjwa (Pkhd1Pk) are phenotypically normal with no liver or kidney pathology observed by 14 months of age. These mice can be used to track the glycolsylation, proteolytic cleavage and shedding of fibrocystin.
The targeting vector was designed with a loxP-STOP-loxP (LSL) cassette containing a puromycin acetyltransferase gene (pac) and four copies of the SV40 viral transcriptional termination sequence inserted into intron 2 and two SV5-Pk epitope tags (26 amino acids long) inserted in-frame into exon 3. The LSL cassette terminates all Pkhd1 transcripts in intron 2. Correctly targeted 129-derived ES cells were injected into recipient blastocysts, and chimeric animals were bred with C57BL/6 mice. Pkhd1LSL mice were backcrossed to BALB/cJ mice for at least ten generations prior to sending to The Jackson Laboratory Repository. Upon arrival, mice were bred to BALB/cJ inbred mice (Stock No. 000651) for at least one generation to establish the colony.
|Allele Name||targeted mutation 2, Christopher J Ward|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Pkhd1, polycystic kidney and hepatic disease 1|
|Strain of Origin||129|
|Molecular Note||The targeting vector was designed with a loxP-STOP-loxP (LSL) cassette containing a puromycin acetyltransferase gene (pac) and 4 copies of the SV40 viral transcriptional termination sequence inserted into intron 2 and two SV5-Pk epitope tags (26 amino acids long) inserted in-frame into exon 3. The LSL cassette terminates all transcripts in intron 2 generating a null allele. Northern blotting and RT-PCR analysis confirmed the absence of mRNA.|
|Mutations Made By|| |
Christopher Ward, University of Kansas Medical Center
Homozygous mice develop progressive polycystic liver disease (~1-3 months in both females and males), as well as kidney disease (worse in females). When maintaining a live colony, heterozygous mice may be bred together, to wildtype mice from the colony, or to BALB/cJ inbred mice (Stock No. 000651).
When using the C.129(B6)-Pkhd1tm2Cjwa/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #021023 in your Materials and Methods section.