B6.129S6(Cg)-Smad4^tm2.1Cxd/WmaoJ

Stock number: 040544
Product name: Smad4^Co/B6
Research areas: Cancer Research, Cell Biology Research, Research Tools

Description

These floxed mutant mice possess loxP sites flanking exon 8 of the MAD homolog 4 (Smad4) gene. This strain may be useful for studying cell proliferation and tumor suppression.

Detailed description

These Smad4^Co floxed mutant mice possess loxP sites flanking exon 8 of the MAD homolog 4 (Smad4) gene. Mice that are homozygous for this allele are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. SMAD4 is a member of a family of intracellular signaling mediators and plays a role as a tumor suppressor. SMAD4 is involved in growth control and transcriptional regulation during development by transmitting signals from the cell surface to the nucleus via the transforming growth factor β (TGFβ) and bone morphogenic protein (BMP) signaling system. When these mutant mice are bred to mice expressing Cre recombinase, resulting offspring will have exon 8 deleted in cre-expressing tissues. This strain may be useful for studying cell proliferation and tumor suppression.

This is a C57BL/6J congenic line of Smad4^Co floxed mutant mice (Stock No. 017462).

Development

The Smad4^Co targeting vector was designed to insert a loxP site upstream of exon 8, and a loxP-flanked neomycin (neo) resistance cassette downstream of exon 8 of the MAD homolog 4 (Smad4) gene. This construct was injected into 129S6/SvEvTac-derived TC1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts, and resulting chimeric males were bred with Black Swiss females. The resulting offspring were bred to Tg(EIIa-cre)C5379Lmgd mice to delete the floxed-neo cassette. Offspring contained multiple gene rearrangements: intact floxed-exon 8, intact floxed-neo cassette, or removal of exons 8 and the neo cassette. Mice containing the floxed-exon were maintained on a mixed background by Dr. Chuxia Deng, University of Macau. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to generate STOCK Smad4^tm2.1Cxd/J mice (Stock No. 017462). In 2018, Dr. Weiming Mao (Indiana University) obtained STOCK Smad4^tm2.1Cxd/J mice from The Jackson Laboratory and backcrossed them to C57BL/6J inbred mice at least 9 generations before sending the mice to The Jackson Laboratory (see SNP note below). Upon arrival at The Jackson Laboratory, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes.



In 2025, 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. Two of the 43 markers throughout the genome were segregating with 129, on Chromosomes 4 and 18. The Chromsome 18 marker is likely a passenger segment from Smad4 mutation.

Allele

Symbol: Smad4^tm2.1Cxd
Name: targeted mutation 2.1, Chu-Xia Deng
MGI accession ID: MGI:2386393
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Synonyms: Smad^flox; Smad4^Co; Smad4^fl; Smad4^flox; Smad4^fx(exon8); Smad4^loxp
Marker symbol: Smad4
Marker name: SMAD family member 4
Marker synonyms: D18Wsu70e; Dpc4; JIP; Madh4; MYHRS; Smad 4
Chromosome: 18
Strain of origin: 129S6/SvEvTac
Molecular note: Exon 8 was left flanked by single loxP sites after the floxed neo cassette was excised by the in vivo expression of cre recombinase.