B6;129-Pax2^tm1.1Gdr/J

Stock number: 018438
Research areas: Developmental Biology Research, Internal/Organ Research, Neurobiology Research, Reproductive Biology Research, Research Tools, Sensorineural Research

Description

This Pax2^Egfp knock-in/knockout strain has its Pax2 gene disrupted by an inserted EGFP sequence. These mice may be useful in applications related to the study of the developing intermediate mesoderm (kidney) and male/female urogenital epithelial structures, renal coloboma syndrome, and renal-specific stem cells.

Detailed description

The Pax2^Egfp knock-in/knockout allele has an EGFP with polyA signal upstream of the endogenous paired box gene 2 (Pax2) translational start site; both abolishing endogenous gene function and placing EGFP expression under direction of the Pax2 promoter/enhancer regions. All mice homozygous for the Pax2^Egfp allele exhibit exencephaly, complete renal agenesis, and die at birth. The donating investigator did not assess if any eye/ear abnormalities were present. Mice heterozygous for the Pax2^Egfp allele are viable, fertile, and phenotypically indistinguishable from wildtype littermate controls (do not exhibit kidney structural defects). In both heterozygous and homozygous mice, EGFP expression (direct fluorescence) is observed in a spatial and temporal pattern consistent with the expected expression of endogenous Pax2. The EGFP expression of Pax2^Egfp heterozygous mice is described in detail below.
At embryonic day (E)9.5, EGFP expression is observed in optic cup, otic vesicle, the midbrain-hindbrain junction, and developing nephric duct. By E10.5, EGFP positive cells of the intermediate mesoderm are segregated into epithelial duct cells and adjacent mesenchyme. By E11.5, EGFP is seen in the ureteric bud and condensing mesenchyme of the metanephric kidney, as well as Pax2-positive neurons that developed at this time along the entire neural tube. At later stages of development, kidney epithelia, ureters, and all the male and female specific epithelia derived from the intermediate mesoderm are EGFP positive. In newborn mice, EGFP expression is strong in the entire nephrogenic zone (nephron differentiation is still ongoing). In adult kidneys, EGFP expression is observed in the renal papilla. When comparing EGFP expression of mice heterozygous for the Pax2^Egfp knockout allele (Stock No. 018438) to mice heterozygous for the Pax2^Eneo hypomorphic allele (Stock No. 018437), there is no qualitative difference in the temporal and spatial pattern of EGFP, although the intensity of EGFP is higher in Pax2^Egfp heterozygotes compared to Pax2^Eneo heterozygotes.

Development

The Pax2-Eneo targeting vector was designed to insert an enhanced green fluorescent protein sequence (EGFP; with polyA signal) and frt-flanked PGK-neo cassette upstream of the translational start site in exon 1 of the paired box gene 2 gene (Pax2). The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts and chimeric males were bred with C57BL/6 females to establish the Pax2^Eneo colony. The donating investigator reports that to remove the frt-flanked PGK-neo cassette, some Pax2^Eneo mice were bred to C57BL/6 animals expressing FLP recombinase. The resulting mice with EGFP and single frt site remaining upstream of the Pax2 coding region were identified. These Pax2^Egfp mice were subsequently bred to wildtype mice for several generations (and the FLP gene was removed). Pax2^Egfp mice on a mixed C57BL/6;129 genetic background were then sent to The Jackson Laboratory Repository. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish The Jackson Laboratory Repository colony.

Allele

Symbol: Pax2^tm1.1Gdr
Name: targeted mutation 1.1, Gregory R Dressler
MGI accession ID: MGI:5427892
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Pax2
Marker name: paired box 2
Chromosome: 19
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: At embryonic day (E)9.5, EGFP expression is observed in optic cup, otic vesicle, the midbrain-hindbrain junction, and developing nephric duct. By E10.5, EGFP positive cells of the intermediate mesoderm are segregated into epithelial duct cells and adjacent mesenchyme. By E11.5, EGFP is seen in the ureteric bud and condensing mesenchyme of the metanephric kidney, as well as Pax2-positive neurons that developed at this time along the entire neural tube. At later stages of development, kidney epithelia, ureters, and all the male and female specific epithelia derived from the intermediate mesoderm are EGFP positive. In newborn mice, EGFP expression is strong in the entire nephrogenic zone (nephron differentiation is still ongoing). In adult kidneys, EGFP expression is observed in the renal papilla.
Molecular note: An EGFP and FRT-flanked neo cassette were inserted upstream of the coding sequence in exon 1. Flp-mediated recombination removed the neo cassette.