B6;129X1-Tyr^c-2J Cdkn1a^tm2Hpw/J

Stock number: 023428
Research areas: Dermatology Research, Mouse/Human Gene Homologs, Research Tools, Sensorineural Research

Description

This mouse strain features a Cre-inducible luciferase reporter gene inserted into exon 2 of the mouse Cdkn1a gene, knocking out expression. Cre-mediated excision of a floxed stop segment enables tissue-specific expression of luciferase under the direction of the endogenous Cdkn1a promoter.

Detailed description

Cdkn1a (cyclin-dependent kinase inhibitor 1A (P21) is a cyclin-dependent protein kinase (CDK) inhibitor that binds to cyclin-CDK complexes, as well as free CDKs, to inhibit cell cycle progression. This inhibition occurs during cell differentiation and in response to DNA damage and oxidative stress. Involvement in metabolic regulation has also been found. Short-term food deprivation (fasting) induces P21 expression in tissues involved in metabolic regulation (including liver).

A loxP-flanked stop codon followed by a luciferase reporter was introduced to exon 2 of the mouse Cdkn1a gene, knocking out normal gene expression. Cre-mediated excision of the floxed stop enables tissue-specific expression of luciferase from the endogenous Cdkn1a promoter.

Liver-specific luciferase expression has been demonstrated when the floxed stop mice are crossed with Alb-cre animals (e.g. Stock No. 003574).

Development

A loxP-flanked neomycin/stop cassette was introduced to exon 2, 5' of the ATG start codon by homologous recombination in 129X1/SvJ-derived SSC10 embryonic stem cells. Codon-optimized click-beetle red luciferase cDNA (Luc) and bovine growth hormone polyadenylation sequences were added just 3' of the start codon. Resultant male chimeras were mated to C57BL/6J females. Mice were subsequently backcrossed to B6(Cg)-Tyr^c-2J/J (see Stock No. 000058) for 3 generations by the donating laboratory.

Allele

Symbol: Cdkn1a^tm2Hpw
Name: targeted mutation 2, Helen Piwnica-Worms
MGI accession ID: MGI:5502584
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Cdkn1a
Marker name: cyclin-dependent kinase inhibitor 1A (P21)
Chromosome: 17
Strain of origin: 129X1/SvJ
Molecular note: A loxP-flanked neomycin/stop cassette was introduced to exon 2, 5' of the ATG start codon by homologous recombination. Codon-optimized click-beetle red luciferase cDNA (CBRLuc) and bovine growth hormone polyadenylation sequences were added just 3' of the start codon.

Allele

Symbol: Tyr^c-2J
Name: albino 2 Jackson
MGI accession ID: MGI:1855985
Generation method: Spontaneous
Attributes: Null/Knockout
Marker symbol: Tyr
Marker name: tyrosinase
Chromosome: 7
Strain of origin: B6.Cg-Tyrp1^b Hps1^ep
Site of expression: Expressed in melanosomes
Molecular note: This mutation has a G-to-T base change at coding nucleotide 230 resulting in an amino acid change from arginine to leucine at residue 77 (p.R77L) which lies in the highly conserved DDRE sequence. Nucleotide 230 is at the alternative 5' splice donor site for exon 1 and this allele does not produce the 1a or 1b subset of tyrosinase transcripts but does produce a significant increase in 1c and 1d transcripts. Western blots of homozygous mutant skin extracts demostrate the nearly complete absence of the broad 76-84 kDa band of glycosylated wild-type tyrosinase. No tyrosinase activity was found in hairbulb extracts from homozygous mice.