B6.129S(Cg)-Id2^tm2.1Blh/ZhuJ

Stock number: 016224
Product name: Id2-eGFP
Research areas: Cell Biology Research, Developmental Biology Research, Endocrine Deficiency Research, Hematological Research, Immunology, Inflammation and Autoimmunity Research, Internal/Organ Research, Reproductive Biology Research, Research Tools

Description

The Id2-eGFP knock-in allele was designed to both abolish Id2 gene function and direct enhanced green fluorescent protein expression from the endogenous Id2 promoter/enhancer elements.

Detailed description

The Id2-EGFP knockin allele was designed to both abolish inhibitor of DNA binding 2 (Id2) gene function and express enhanced green fluorescent protein (eGFP) from the Id2 promoter/enhancer elements. No Id2 expression is observed from the endogenous Id2 gene. The donating investigator reports that homozygote mice mice are runted with defective lung alveolarization. Other organ systems have not been evaluated. However, Id2-eGFP homozygotes may be expected to exhibit the same phenotype as mice homozygous for other null mutations of this gene (including postnatal lethality and defects of the immune system, digestive tract, kidneys, adipose tissue and mammary gland development). The donating investigator also reports eGFP expression recapitulates the endogenous Id2 expression pattern. In the lungs, immunohistochemical detection of eGFP recapitulates the epithelial expression of the endogenous gene (distal tip lung epithelial multipotent precursor cells of the developing lung throughout branching morphogenesis up to embryonic day (E)16.5). The donating investigator reports immunohistochemical and FACS detection of eGFP in immune cell populations is observed for single-positive CD4 thymocytes and single-positive CD8 thymocytes, CD4-positive splenocytes, and CD8-positive splenocytes. No eGFP expression is observed in CD4/CD8 double-positive thymocytes, and direct eGFP fluorescence was too weak to be observed microscopically for any cell type. Heterozygous mice are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities.

Of note, the same group designed an identically-targeted Id2-CreERT2 knockin mouse line to express the tamoxifen-inducible CreER^T2 fusion protein (rather than eGFP) from the Id2 promoter/enhancer elements. That Id2-CreERT2 knockin mouse line is available as Stock No. 016222.

Development

The Id2-eGFP knockin mutation was created by the laboratory of Dr. Brigid LM Hogan (Duke University Medical Center). A targeting vector was designed to insert an enhanced green fluorescent protein gene (followed by an frt-flanked PGK-neo cassette) into the translation initiation codon of the inhibitor of DNA binding 2 locus (Id2); replacing most of exon 1 except the final 25 nucleotides. The targeting construct was electroporated into 129SvEv-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts and chimeric mice were bred with C57BL/6NCrl mice to originate the colony. Mutant mice were bred with ROSA26-FLPe mice (on an uncharacterized genetic background) to remove the PGK-neo selection cassette. These Id2-eGFP knockin mice were subsequently bred to C57BL/6NCrl mice for 5-8 generations (and the ROSA26-FLPe was removed). Next, heterozygous mutant mice were sent to Dr. Yuan Zhang (Duke University) where they were backcrossed to C57BL/6J mice for at least one additional generation prior to sending to The Jackson Laboratory Repository. Upon arrival, Id2-eGFP knockin mice were bred with C57BL/6NJ inbred mice (Stock No. 005304) for at least one generation to establish the Id2-eGFP knockin colony. During backcrossing, the Y chromosome may not have been fixed to the C57BL/6 genetic background.

Allele

Symbol: Id2^tm2.1Blh
Name: targeted mutation 2.1, Brigid L Hogan
MGI accession ID: MGI:4398924
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Id2
Marker name: inhibitor of DNA binding 2
Chromosome: 12
Strain of origin: 129S/SvEv
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: EGFP is expressed in epithelial cells of the lung and in immune cell populations.
Molecular note: The targeting vector contained an EGFP cassette inserted at the translation initiation codon of the Id2 locus, replacing most of exon 1, except for the final 25 nucleotides. The cre cassette was followed by a frt-PGK-neo-frt cassette, which was removed by flp-mediated excision after germline transmission.