B6(Cg)-Tg(Phox2b-cre)3Jke/J

Stock number: 016223
Product name: Phox2b-Cre line 3
Research areas: Developmental Biology Research, Internal/Organ Research, Metabolism Research, Mouse/Human Gene Homologs, Neurobiology Research, Research Tools

Description

Phox2b-Cre BAC transgenic mice have Cre recombinase expression directed primarily to the hindbrain by the Phox2b promoter/enhancer regions, and may be used to generate conditional mutations for studying neuronal cell types expressing or depending on the Phox2b transcription factor. Specifically, these mice may be useful for studying human respiratory disease, central chemoreceptive neurons in the retrotrapezoid nucleus, respiratory rhythmogenesis, and autonomic nervous system dysregulation (such as congenital central hypoventilation syndrome (CCHS) or Ondine-Hirschsprung disease).

Detailed description

Phox2b-Cre BAC transgenic mice are viable and fertile, with Cre recombinase expression under control of the Phox2b promoter/enhancer regions within the BAC transgene. cre-expressing neurons co-express PHOX2B (as shown by in situ hybridization). Phox2b-Cre BAC transgenic mice from founder line 3 exhibit cre expression directed primarily to the hindbrain; specifically the dorsal motor nucleus of the vagus (DMV) in parasympathetic visceral and branchial motor neurons, nodose sensory ganglia, and nucleus of the solitary tract (NTS) cells. No transgene expression is reported in hypothalamus or spinal cord. Although endogenous Phox2b expression is reported in peripheral ganglia along with the enteric nervous system, no peripheral transgene expression is reported for these Phox2b-Cre BAC transgenic mice. When bred with mice containing a loxP-flanked sequence of interest, Cre-mediated recombination will result in deletion of the floxed sequences in the offspring. These Phox2b-Cre BAC transgenic mice may be used to generate conditional mutations for studying neuronal cell types expressing/depending on the Phox2b transcription factor for energy balance, glucose homeostasis, and autonomic breathing/respiration. Specifically, these mice may be useful for studying human respiratory disease, central chemoreceptive neurons in the retrotrapezoid nucleus, respiratory rhythmogenesis, and autonomic nervous system dysregulation (such as congenital central hypoventilation syndrome (CCHS) or Ondine-Hirschsprung disease).

For example, when Phox2b-Cre BAC transgenic mice are bred with floxed leptin receptor mice (Stock No. 008327), the resulting offspring allow studying hindbrain nucleus of the solitary tract (NTS) leptin receptor function in NTS appetite, hunger, and food consumption.

Development

The Phox2b-Cre BAC transgene was designed in the laboratory of Dr. Joel K. Elmquist (University of Texas Southwestern Medical Center at Dallas). The C57BL/6J mouse bacterial artificial chromosome (BAC) RP24-95M11, containing the entire Phox2b locus was obtained. This BAC also contained ~130kb sequence upstream of the Phox2b locus (including part of the Limch1 locus) and ~70kb of sequence downstream of the Phox2b locus. A Cre recombinase sequence fused with an frt-flanked neomycin gene was inserted into the ATG start site of the Phox2b locus on the RP24-95M11 BAC via homologous recombination/BAC recombineering. The frt-flanked neo was removed via transient transfection of an FLP-expressing vector during BAC recombineering. The resulting ~200 kb Phox2b-Cre BAC transgene was injected into C57BL/6J mouse pronuclei to produce independent founder lines. Transgenic founders were bred with ROSA-lacZ mice (on a mixed B6;129- or C57BL/6-congenic background; see Stock Nos. 003309 or 003474). Founder line 3 was found with the greatest degree of nucleus of the solitary tract (NTS) cells expressing Cre recombinase. Mice from founder line 3 were subsequently backcrossed to C57BL/6J mice for at least ten generations (and the ROSA-lacZ mutation removed) prior to sending 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 colony.

In 2017, a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 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. One of the 43 markers, at the thymus cell antigen 1, theta (Thy1) gene was segregating.

Allele

Symbol: Tg(Phox2b-cre)3Jke
Name: transgene insertion 3, Joel K Elmquist
MGI accession ID: MGI:5005058
Generation method: Transgenic
Attributes: Recombinase-expressing
Marker symbol: Tg(Phox2b-cre)3Jke
Marker name: transgene insertion 3, Joel K Elmquist
Chromosome: UN
Strain of origin: C57BL/6J
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: cre expression is directed primarily to the hindbrain; specifically the dorsal motor nucleus of the vagus in parasympathetic visceral and branchial motor neurons, nodose sensory ganglia, and nucleus of the solitary tract cells.
Molecular note: The mouse BAC RP24-95M11, containing the entire Phox2b locus and 130kb sequence upstream of the Phox2b locus (including part of the Limch1 locus) and 70kb of sequence downstream of the Phox2b locus was modified to produce the construct. A Cre recombinase sequence fused with an frt-flanked neomycin gene was inserted into the ATG start site of the Phox2b locus via homologous recombination/BAC recombineering. The frt-flanked neo was removed via transient transfection of an FLP-expressing vector during BAC recombineering. The resulting ~200 kb Phox2b-Cre BAC transgene was injected into C57BL/6J mouse pronuclei to produce independent founder lines. Founder line 3 was found with the greatest degree of nucleus of the solitary tract (NTS) cells expressing Cre recombinase.