B6(Cg)-Esr2^{tm1.1(icre)Jako}/J

Stock number: 028717
Product name: Esr2-iCre
Research areas: Reproductive Biology Research, Research Tools

Description

These Esr2-iCre knock-in/knock-out mice express codon optimized Cre recombinase from the endogenous Esr2 locus. Cre recombinase expression mimics endogenous Esr2 gene expression.

Detailed description

The targeted Esr2 gene encodes the nuclear receptor estrogen receptor-beta, and is expressed broadly throughout the mouse. These Esr2-iCre mice have iCre (codon-improved Cre recombinase) inserted into the initiation codon site of exon 2 of the Esr2 gene, which encodes DNA binding central C domain of estrogen receptor beta. When crossed with a strain containing loxP site flanked sequence of interest, Cre-mediated recombination results in deletion of the floxed sequence in the cre expressing tissues. iCre recombinase expression mimics the endogenous Esr2 gene expression pattern. Cre recombinase expression is detected in pituitary, hypothalamus, mucosa of the colon and cecum, lung, respiratory epithelium, skeletal muscle, ovarian granulosa, theca and stroma cells, testes (seminiferous tubule interstitium, Leydig cells), epididymis, ductus deferens, coagulation gland (anterior prostate) epithelium, and prepucial glands. Punctate Cre recombinase activity is detected in mice 2 months of age or older, in the epithelial cells and in the muscularis layer of the oviduct, uterus, stratified mucosa of vagina, rete testes epithelium, epididymal epithelium at the head and tail, vas deferens epithelium, cerebral forebrain neurons, cerebellum and ventral cerebrum, cardiac epicardium and atrial myocardium, salivary glands, adrenal gland, and mucosa/submucosa of intestine. Low levels of expression is detected in detrusor muscle of the bladder, cornea, Peyers patches, pancreas, pads of feet, and in a few cells per hair follicle. Of note, when maternally inherited the Esr2-iCre allele may have widespread expression (due to expression in some oocytes). No gene product (mRNA) is detected by RT-PCR analysis of ovary tissue from homozygous females. Male mice that are homozygous for the targeted mutation are viable and fertile, but female homozygotes are infertile and exhibit irregular cyclicality with longer periods of estrus or diestrus. Heterozygotes are viable and fertile.

Development

A targeting vector containing iCre (codon-improved Cre recombinase), a polyadenylation sequence, and an FRT site flanked PGK-NEO cassette was inserted into the initiation codon site of exon 2 of the targeted gene. The construct was electroporated into B6(Cg)-Tyrc-2J/J-PRX-B6-albino #1 mES cells (Stock No. 012813). Correctly targeted ES cells were injected into blastocysts. The resulting male chimeric animals were bred to albino C57BL/6J females to achieve germline transmission.

The mice were then crossed to B6N.Cg-Tg(ACTFLPe)9205Dym/CjDswJ (Stock No. 019100) to remove the FRT site flanked selection cassette. The mice were maintained on a C57BL/6J mice and were bred to eliminate the FLP transgene.

Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

Allele

Symbol: Esr2^{tm1.1(icre)Jako}
Name: targeted mutation 1.1, CheMyong Ko
MGI accession ID: MGI:5907833
Generation method: Targeted
Attributes: Recombinase-expressing
Marker symbol: Esr2
Marker name: estrogen receptor 2 (beta)
Chromosome: 12
Strain of origin: C57BL/6NTac
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: When crossed with a strain containing loxP site flanked sequence of interest, Cre-mediated recombination results in deletion of the floxed sequence in the cre expressing tissues. iCre recombinase expression mimics the endogenous Esr2 gene expression pattern.
Molecular note: A targeting vector containing iCre (codon-improved Cre recombinase), a polyadenylation sequence, and an FRT site flanked PGK-NEO cassette was inserted into the initiation codon site of exon 2 of the targeted gene. Flp-mediated recombination removed the FRT-flanked neo cassette.