B6;129S-Gt(ROSA)26Sor^{tm1(Cdkn1c)Jfpa}/J

Stock number: 022516
Product name: R26loxpTA-p57^k
Research areas: Apoptosis Research, Cancer Research, Cell Biology Research, Neurobiology Research, Research Tools

Description

R26loxpTA-p57 mice allow Cre recombinase-inducible expression of the cell cycle inhibitor p57^Kip2 (Cdkn1c), resulting in cell cycle arrest in G1 phase of the cre expressing cells.

Detailed description

The R26loxpTA-p57 allele has a loxP-flanked transcriptional termination cassette upstream of a mouse p57^Kip2 (Cdkn1c) cDNA sequence, all inserted into the Gt(ROSA)26Sor locus. Although under control of the Gt(ROSA)26Sor promoter, widespread expression of p57^Kip2 is prevented by the upstream floxed-STOP cassette in the absence of Cre recombinase. Heterozygous mice (R26loxpTA-p57^k/+) are viable and fertile with no reported phenotypic abnormalities. The donating investigator reports that homozygous mice (R26loxpTA-p57^k/k) have the same phenotype as heterozygous mice.

When bred to mice that express Cre recombinase, offspring will have the floxed-STOP cassette deleted in cre-expressing cells; resulting in p57^Kip2 expression and subsequent cell cycle inhibition/arrest in G1 phase.

For example, when R26loxpTA-p57 mice are bred with mice expressing Cre recombinase in myocardial cells (Mlc2v-Cre knockin), the myocardial specific p57Kip2 expression in the embryonic and adult ventricular cardiomyocytes attenuates hypoxic-ischemic injury.

Development

The R26loxp-TAp57 targeting sequence was designed with (from 5' to 3') a splice acceptor, a loxP-flanked strong transcriptional termination sequence (PGK-neo-polyA [tpA]), a 1.4 kbp cDNA containing the complete open reading frame of mouse p57^Kip2 (Cdkn1c), and a bovine polyA signal.

The p57^Kip2 sequence encodes the mouse Cdkn1c [cyclin-dependent kinase inhibitor 1C (P57)] protein that functions as a cell cycle inhibitor by binding to G1 cyclin-CDK complexes and causing arrest of the cell cycle in G1 phase.

The R26loxp-TAp57 construct was inserted between exons 1 and 2 of the Gt(ROSA)26Sor locus on chromosome 6 via electroporation of 129S7/SvEvBrd-Hprt^b-m2 derived AB2.2 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts and chimeric males were bred with C57BL/6-Tyr^c-Brd females to obtain F1 progeny. The resulting R26loxpTA-p57 mice were maintained on a mixed C57BL/6;129/Sv background prior to sending to The Jackson Laboratory in 2009. Upon arrival, sperm was cryopreserved. To generate our living R26loxpTA-p57 mouse colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J females (Stock No. 000664).

Allele

Symbol: Gt(ROSA)26Sor^{tm1(Cdkn1c)Jfpa}
Name: targeted mutation 1, James Padbury
MGI accession ID: MGI:5492378
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); Inserted expressed sequence
Marker symbol: Gt(ROSA)26Sor
Marker name: gene trap ROSA 26, Philippe Soriano
Chromosome: 6
Strain of origin: 129S7/SvEvBrd-Hprt^b-m2
Expressed genes: Cdkn1c,cyclin-dependent kinase inhibitor 1C (P57),mouse, laboratory
Molecular note: A 1.4 kb cDNA containing the complete open reading frame of the mouse gene was placed under the control of a loxP-flanked transcriptional termination sequence. This construct was inserted between exons 1 and 2.