Pah KO Mice

Catalog Number: C001560

Strain Name: C57BL/6JCya-Pahem1/Cya

Genetic Background: C57BL/6JCya

Reproduction: Heterozygote × Heterozygote

 

Strain Description

Phenylalanine hydroxylase (PAH) is a member of the biotin-dependent aromatic amino acid hydroxylase protein family encoded by the PAH gene. The main function of PAH is to hydroxylate phenylalanine (Phe) into tyrosine (Tyr), a crucial step in phenylalanine catabolic metabolism. Lack of PAH activity can lead to the autosomal recessive inherited disorder phenylketonuria (PKU), also known as PAH deficiency. PKU is a congenital disease caused by pathogenic variants in the PAH gene and belongs to the group of amino acid metabolic disorders. Patients with PKU excrete large amounts of phenylketones and other metabolites in their urine. In PKU patients, deficiency of the PAH enzyme results in elevated blood phenylalanine (Phe) levels, leading to brain dysfunction. Untreated PKU patients may experience severe and irreversible intellectual disabilities, seizures, behavioral disturbances, microcephaly, epilepsy, psychological symptoms, and generalized hypopigmentation of the skin (including hair and eyes). Approximately 1 in 24,000 individuals is affected by PKU [1-2].

The Pah KO mice is a phenylketonuria (PKU) disease model generated by knocking out the Pah gene in mice using gene editing techniques. In this model, both Pah mRNA and PAH protein expression are completely absent, leading to PKU-related phenotypes associated with impaired phenylalanine (Phe) catabolic metabolism. As blood Phe levels rise and Tyr levels decrease in the mouse, the pigmentation of their fur gradually fades, and by 8 weeks of age, their fur color becomes entirely brown. Consequently, Pah KO mice serve as valuable tools for studying the genetic mechanisms of PKU in humans and for the preclinical evaluation of therapeutic drugs.

Strain Strategy

The Pah gene is located on chromosome 10 in mice, and knocking out exon 3 of the mouse Pah gene using gene editing technology resulted in a strain with a deletion of Pah gene expression.


Application

1. Research on the genetic mechanism of phenylketonuria (PKU) and the preclinical evaluation of therapeutic drugs;

2. Research related to protein metabolism, nervous system, pigmentation, etc.

Validation Data

1. Detection of mRNA expression level

Figure 1. Pah mRNA expression analysis in 12-week-old Pah KO mice and wild-type mice (WT). RT-qPCR results revealed that Pah mRNA expression was absent in both the liver and kidneys of Pah KO mice.

2. Detection of protein expression level


Figure 2. Protein expression analysis in 12-week-old male Pah KO mice and wild-type mice (WT)*. Western blot results revealed that PAH protein expression was absent in both the liver and kidneys of Pah KO mice.

*The detection was performed using recombinant Anti-PAH antibody [EPR12380] provided by Abcam (catalog number: ab178430).

3. Survival and growth curves


Figure 3. Survival and growth curves of Pah KO mice. The results indicate that Pah KO mice fed a normal chow diet have a median survival period of approximately 5 weeks. Compared to wild-type mice, Pah KO mice exhibit significantly lower body weight between 4 and 12 weeks of age.

4. Coat color changes in Pah KO mice

Figure 4. Coat Color in Pah KO Mice. The results indicate that due to continuously elevated phenylalanine (Phe) levels and decreased tyrosine (Tyr) levels in the mouse bloodstream, the fur pigmentation fades. By 8 weeks of age, the mouse fur completely changes to brown.

5. Phenylalanine and tyrosine concentration assays


Figure 5. Phenylalanine (Phe) and Tyrosine (Tyr) Levels in 12-Week-Old Pah KO Mice and Wild-Type Mice (WT). The results indicate that compared to wild-type mice, Pah KO mice exhibit significantly elevated Phe concentrations and markedly reduced Tyr concentrations, consistent with the phenylketonuria (PKU) phenotype.

 

References

[1] Elhawary NA, AlJahdali IA, Abumansour IS, Elhawary EN, Gaboon N, Dandini M, Madkhali A, Alosaimi W, Alzahrani A, Aljohani F, Melibary EM, Kensara OA. Genetic etiology and clinical challenges of phenylketonuria. Hum Genomics. 2022 Jul 19;16(1):22.
[2] MedlinePlus Genetics. PAH gene. U.S. National Library of Medicine. https://medlineplus.gov/genetics/gene/pah/