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Published on: September 1, 2015
A functional floxed allele of Pkd1 that can be conditionally inactivated in vivo
Klaus B Piontek1, David L Huso, Alexander Grinberg
1Department of Medicine, Division of Nephrology, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, MD 21205, USA.
Abstract:
Gene targeting has been used to create a variety of lines of mice with Pkd1 mutations that share many common features. Homozygous Pkd1 mutants invariably develop pancreatic and renal cysts if they survive to day 15.5 post coitum and die in either the fetal or the perinatal period. In contrast, mice with heterozygous mutations of Pkd1 are generally normal and have few if any renal cysts. These features have limited the utility of these models as tools to study the pathogenesis of cyst formation and the effect of various therapeutic interventions on disease progression. This report describes a new line of mice with a floxed allele of Pkd1 (Pkd1(cond)) that has an FRT-flanked neomycin cassette inserted into intron 1 and lox P sites inserted into intron 1 and intron 4. The Pkd1(cond) allele is fully functional, and homozygotes are viable and healthy. It is shown that the lox P and FRT sites can be selectively induced to recombine to produce two new alleles, Pkd1(del2-4) and Pkd1(cond-Deltaneo), by crossing to animals that express either the cre or FLPe recombinase, respectively. It is found that Pkd1(del2-4) allele functions as a true null, whereas presence or absence of the neomycin gene has no functional effects. It also is shown that somatic loss of Pkd1 results in renal and hepatic cysts. This new line of mice will be invaluable in the study of Pkd1 biology and serve as a powerful new tool that can be used to study the pathogenesis of autosomal dominant polycystic kidney disease.
Insights
A new mouse model with a conditional Pkd1 (polycystic kidney disease 1) allele allows for targeted gene deletion. Somatic Pkd1 loss in these mice induces renal and hepatic cysts, aiding polycystic kidney disease research.
Area of Science:
- Genetics
- Developmental Biology
- Animal Models
Background:
- Existing Pkd1 mutant mouse models have limitations for studying polycystic kidney disease (PKD) pathogenesis and therapeutic interventions.
- Homozygous Pkd1 mutants exhibit severe phenotypes, while heterozygous mutants show minimal cyst formation, restricting their utility.
- A need exists for more refined genetic tools to investigate Pkd1 function and PKD development.
Purpose of the Study:
- To develop and characterize a novel mouse line with a conditional Pkd1 allele (Pkd1(cond)) for precise genetic manipulation.
- To demonstrate the ability to generate distinct Pkd1 alleles (Pkd1(del2-4) and Pkd1(cond-Deltaneo)) using Cre and FLPe recombinase systems.
- To investigate the in vivo consequences of somatic Pkd1 loss on cystogenesis.
Main Methods:
- Generation of a Pkd1(cond) mouse line featuring FRT-flanked neomycin cassette and lox P sites.
- Induction of recombination via Cre or FLPe recombinase to generate Pkd1(del2-4) and Pkd1(cond-Deltaneo) alleles.
- Analysis of Pkd1 allele function and induction of somatic Pkd1 loss to observe cyst formation.
Main Results:
- The Pkd1(cond) allele is fully functional, with homozygotes being viable and healthy.
- Selective recombination yields Pkd1(del2-4) (true null) and Pkd1(cond-Deltaneo) alleles.
- Somatic loss of Pkd1 in mice leads to the development of renal and hepatic cysts, mimicking PKD phenotypes.
Conclusions:
- The Pkd1(cond) mouse line provides a versatile tool for studying Pkd1 biology.
- This model enables conditional and somatic inactivation of Pkd1, crucial for investigating autosomal dominant polycystic kidney disease (ADPKD) pathogenesis.
- The developed mouse line will significantly advance research into PKD mechanisms and potential therapeutic strategies.
