STOCK Foxa2^tm1Khk/J

Stock number: 022620
Product name: HNF3β^loxP
Strain synonyms: Foxa2^flox, Foxa2^loxP
Research areas: Developmental Biology Research, Internal/Organ Research, Metabolism Research, Research Tools

Description

These Foxa2^loxp/loxp mutant mice possess loxP sites flanking exon 3 of the forkhead box A2 (Foxa2) gene. This strain may be useful for studying the role of HNF3β on embryonic development and metabolism regulation.

Detailed description

These Foxa2^loxp/loxp mutant mice possess loxP sites flanking exon 3 of the forkhead box A2 (Foxa2) gene. Also known as hepatocyte nuclear factor 3 β (HNF3β), FOXA2 is a transcription factor involved in embryonic development, cellular differentiation, and gene expression during liver, pancreas and lung development. FOXA2 plays a role in glucose homeostasis and fat metabolism. Mice that are homozygous for this allele are viable and fertile. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exon 3 deleted in cre-expressing tissues.

For example, when crossed to B6.Cg-Tg(Ins2-cre)25Mgn/J mice (Stock No. 003573) expressing Cre recombinase in pancreatic beta cells, double mutant mice exhibit abnormal islet and beta cell morphology and decreased glucagon secretion. They also have elevated glycogen and insulin levels.

When crossed to B6.Cg-Tg(SFTPC-rtTA)5Jaw/J (Stock No. 006235) and B6.Cg-Tg(tetO-cre)1Jaw/J (Stock No. 006234) mice with doxycycline inducible Cre recombinase expression under the indirect control of the human SFTPC, surfactant, pulmonary-associated protein C, promoter, triple mutant mice develop severe pulmonary distress on the first day of life similar to respiratory distress syndrome in preterm infants.

When crossed to B6.Cg-Tg(Scgb1a1-rtTA)1Jaw/J (Stock No. 006232) and B6.Cg-Tg(tetO-cre)1Jaw/J (Stock No. 006234) mice with doxycycline inducible Cre recombinase expression under the indirect control of the rat secretoglobulin (uteroglobulin) promoter (expression in respiratory epithelial cells), triple mutant mice develop airspace enlargement, goblet cell hyperplasia and increased mucin and neutrophilic infiltration in lungs.

Development

A targeting vector was designed to insert a loxP site upstream of exon 3, and a loxP-flanked neomycin resistance (neo) cassette downstream of exon 3 of the forkhead box A2 (Foxa2) gene. The construct was electroporated into 129P2/OlaHsd-derived E14.1 embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a pIC-Cre expression plasmid to delete the neo cassette. Resulting ES cells contained multiple gene rearrangments; intact floxed-exon 3, intact floxed-neo cassette, or excision of both exon 3 and the neo cassette. Correctly targeted ES cells, containing only the floxed-exon 3, were injected into C57BL/6J blastocysts and resulting chimeric males were bred with C57BL/6 females. Resulting offspring were bred to CD-1 mice and were subsequently bred to C57BL/6 mice for at least 5 generations. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. Nine of 27 markers throughout the genome, as well as 5 of 5 markers that determine C57BL/6J from C57BL/6N, were found to be segregating. Two markers were from an unknown source. This suggests a contamination from an unknown source or incomplete backcross.

Allele

Symbol: Foxa2^tm1Khk
Name: targeted mutation 1, Klaus H Kaestner
MGI accession ID: MGI:2177337
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Foxa2
Marker name: forkhead box A2
Chromosome: 2
Strain of origin: 129P2/OlaHsd
Molecular note: A single loxP site was inserted into intron 2 and a loxP flanked neomycin and thymidine kinase selection cassette was inserted into intron 3. The selection cassette was removed in ES cells by transient Cre expression prior to the production of chimeric mice, leaving exon 2 flanked by loxP sites in the final allele.