129-Tgfb1^{tm1(Tgfb3)Kul}/J

Stock number: 024931
Research areas: Diabetes and Obesity Research, Endocrine Deficiency Research, Internal/Organ Research

Description

TGF-β1^L-β3/L-β3 mice express Tgfb3 cDNA under control of the Tgfb1 LAP. These mice may be useful for studying the phenotypic differences elicited by TGF-β isoforms.

Detailed description

TGF-β1^L-β3/L-β3 mice contain an HA-tagged transforming growth factor, beta 3 (Tgfb3) cDNA, and a frt-flanked neo cassette, expressed under control of the transforming growth factor, beta 1 (Tgfb1) promoter/enhancer sequences. TGFB isoforms are important cytokines that influence cell growth, cell differentiation, apoptosis, and cellular homeostasis. Each isoform contains a latency associated peptide (LAP) domain, required for localization and activation, and a receptor binding ligand, required for cell signaling. Each LAP sequences only shares 40% sequence homology between isoforms, while the ligands share 80% homology and all contain nine conserved cysteines. All three TGF-β proteins have distinct cell-specific expression patterns that reflect the differences in the promoters located within each homologue's gene. In these TGF-β1^L-β3/L-β3 mice, the TGF-β1 LAP is maintained for localization and activation but cell signaling occurs through the TGF-β3 ligand. These mice do not exhibit the embryonic lethality, vasculogenesis defects, or autoimmunity associated with TGF-β1 deficiency. These TGF-β1^L-β3/L-β3 mice have a shortened lifespan and display tooth and bone mineralization defects. These mice display an improved metabolic phenotype with reduced body weight gain and enhanced glucose tolerance, by induction of beneficial changes to the white adipose tissue compartment. These mice also exhibit no defects in palate development. Homozygotes are viable and fertile, with a median survival of 30.5 weeks.

Development

A targeting vector was designed with the transcriptional start site, and exon 1 and intron 1, of the transforming growth factor, beta 1 (Tgfb1) gene driving expression of an HA-tagged transforming growth factor, beta 3 (Tgfb3) cDNA. A loxP-flanked neomycin resistance cassette, in reverse orientation to the gene, was placed immediately downstream. This 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 C57BL/6NCrl Blastocysts and chimeric mice were bred together. These TGF-β1^L-β3/L-β3 mice were maintained by sibling matings. Upon arrival at The Jackson Laboratory, mice were bred with 129S1/SvImJ inbred mice (Stock No. 002448) for at least one generation to establish the colony.

Allele

Symbol: Tgfb1^{tm1(Tgfb3)Kul}
Name: targeted mutation 1, Ashok B Kulkarni
MGI accession ID: MGI:5559039
Generation method: Targeted
Marker symbol: Tgfb1
Marker name: transforming growth factor, beta 1
Chromosome: 7
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: Tgfb3,transforming growth factor, beta 3,mouse, laboratory
Molecular note: The HA-tagged coding sequence for Tgfb3 fused with the sequence of the endogenous gene's latency associated peptide (LAP) and followed by a floxed neomycin resistance cassette replaced exon 2. ELISA confirmed the absence of protein expression in the serum. Western blot analysis confirmed the expression of the HA-tagged protein.