C57BL/6-Atraid^{tm1a(EUCOMM)Hmgu}/EosJ

Stock number: 026576
Research areas: Developmental Biology Research, Internal/Organ Research, Research Tools

Description

Exons 3-5 of the mouse Atraid (TBONE) gene are flanked by loxP sites in this lacZ reporter-tagged conditional mutant strain. Cre-mediated excision of the floxed region results in a knockout allele useful in studies of osteoporosis and nitrogenous bisphosphate (NBP) therapies.

Detailed description

Nitrogenous bisphosphates (NBPs), having an anti-proliferative effect on cells, are commonly-prescribed for the treatment of osteoporosis. Target of BisphOsphonate NitrogEnous (TBONE; formal name Atraid, all-trans retinoic acid induced differentiation factor) is a novel NBP target gene required for the molecular and cellular effects of NBPs on bone. It is a founding component of a mineralization-regulating and mammalian nitrogenous phosphonate-sensing pathway.

Exons 3-5 of the TBONE/Atraid gene are flanked by loxP sites in this lacZ reporter-tagged conditional mutant strain. Cre-mediated excision of the floxed region results in a knockout allele.

Homozygous knockout mice, created through crosses with CMV-cre animals, are viable but have low body mass, deregulated markers of bone remodeling and impaired therapeutic responses to Alendronate (a drug used to treat osteoporosis). Basal levels of the active (nuclear) form of NFATC1 protein, essential for the formation of both osteoblasts and osteoclasts, are reduced and calcium-induced nuclear accumulation is strongly diminished. As judged by markers of calcium (Alizarin Red) and phosphate (Von Kossa) precipitation, TBONE knockdown strongly impairs osteoblast differentiation. Evidence suggests that naturally occurring nitrogenous phosphonates (NPs) regulate mineralization in a TBONE-dependent manner and TBONE is critical for the anti-resorptive effects of NBPs on bone in mice.

As 11/2014, the lacZ reporter component of this allele has not yet been tested.

Development

Embryonic stem (ES) cell clone HEPD0577_2_D01 (IMPC Product: 72859) was created as part of the Knockout Mouse Project (KOMP). This gene-trapped allele of Atraid incorporates an FRT-En2 splice acceptor (SA)-IRES-lacZ-SV40 polyadenylation signal (pA)-loxP-hbactP-Neo-pA-FRT-loxP sequence in intron 2 of the gene and an additional loxP site in intron 5 to create the “knockout first” (tm1a(EUCOMM)Hmgu) allele. C57BL/6N-A^tm1Brd-derived JM8A1.N3 embryonic stem (ES) cells were used to create the mutation. This strain was backcrossed to C57BL/6J for 2 generations by the donating laboratory.

Allele

Symbol: Atraid^{tm1a(EUCOMM)Hmgu}
Name: targeted mutation 1a, Helmholtz Zentrum Muenchen GmbH
MGI accession ID: MGI:4436200
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); Reporter; Null/Knockout
Marker symbol: Atraid
Marker name: all-trans retinoic acid induced differentiation factor
Chromosome: 5
Strain of origin: C57BL/6N-A^tm1Brd
Molecular note: The L1L2_Bact_P cassette was inserted at position 31051591 of Chromosome 5 upstream of the critical exon(s) (Build GRCm38). The cassette is composed of an FRT site followed by lacZ sequence and a loxP site. This first loxP site is followed by a neomycin resistance gene under the control of the human beta-actin promoter, SV40 polyA, a second FRT site and a second loxP site. A third loxP site is inserted downstream of the targeted exon(s) at position 31053173. The critical exon(s) is/are thus flanked by loxP sites. A "conditional ready" (floxed) allele can be created by flp recombinase expression in mice carrying this allele. Subsequent cre expression results in a knockout mouse. If cre expression occurs without flp expression, a reporter knockout mouse will be created. Further information on targeting strategies used for this and other IKMC alleles can be found at http://www.informatics.jax.org/mgihome/nomen/IKMC_schematics.shtml