B6(Cg)-Ptgs1^{tm2.1(Ptgs2)Fun}/J

Stock number: 032327
Product name: COX-2>COX-1, Ptgs2>Ptgs1
Research areas: Endocrine Deficiency Research, Immunology, Inflammation and Autoimmunity Research, Reproductive Biology Research, Research Tools

Description

COX-2>COX-1 knock-in/knock-out mice express Ptgs2 from the endogenous Ptgs1 locus, resulting in widespread expression of cyclooxygenase 2. They are suitable for use in applications related to the study of cyclooxygenase 2 and prostaglandin synthesis pathway.

Detailed description

There are two major cyclooxygenase isoforms in mammals that catalyze prostaglandin biosynthesis and are the targets of nonsteroidal anti-inflammatory drugs. The Ptgs2 gene encodes prostaglandin-endoperoxide synthase 2, also called cyclooxygenase 2 (COX2), which can be induced by inflammation and mitogens. The Ptgs1 gene encodes prostaglandin-endoperoxide synthase 1, also called cyclooxygenase 1 (COX1), has more widespread expression than Ptgs2, is involved in basal prostaglandin synthese. These COX-2>COX-1 knock-in/knock-out mice express Ptgs2 from the endogenous Ptgs1 locus, resulting in expression of cyclooxygenase 2 in liver, spleen, lung, kidney, brain, stomach, and testis. No Ptgs1 gene product (protein) is detected by western blot analysis of kidney, brain, stomach, and testis tissue from homozygous mice. The level of mutant COX2 protein appears to correlate approximately with the level of endogenous COX-1 protein levels in wildtype mice in the respective tissues. Hybrid transcripts are detected by qPCR in brain, liver, kidney, stomach, testis, uterus, and lung; with weaker expression detected in spleen and resident macrophages. Western blot analysis does not detect COX1 protein expression, while hybrid COX2 protein is detected, in non-LPS-stimulated macrophages. In the presence of LPS stimulation, prostanoid production from COX-2>COX-1 macrophages was comparable with that from wildtype mice. Prostaglandin and thromboxane synthesis by the knock-in hybrid COX2 in kidney is reduced in neonate (P8) and adult mutant mice. Homozygotes are viable and fertile.

When crossed to the COX-1>COX-2 knock-in strain (Stock No. 008104) the resulting double mutant mice are the Reversa mouse in which expression of both prostaglandin-endoperoxide synthase (COX) isoforms are interchanged. The Reversa model has applications in studies related to the unique and compensatory functions of the two cyclooxygenase isoforms.

Development

A targeting vector containing a fragment of the Ptgs2 gene with exons 2 through 10 and intronic sequences, and a floxed Neo cassette was used to disrupt exons 3 through 10 of the Ptgs1 gene. The promoter region encoded by exons 1 and 2, and the 3'UTR of the Ptgs1 gene remain intact. The construct was electroporated into unspecified C57BL/6 derived embryonic stem (ES) cells (Cyagen Biosciences, Inc.). Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric males were bred to albino C57BL/6J mice (Stock No. 000058) and targeted male progeny were bred to B6.FVB-Tg(EIIa-cre)C5379Lmgd/J mice (Stock No. 003724) to excise the floxed Neo cassette. 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: Ptgs1^{tm2.1(Ptgs2)Fun}
Name: targeted mutation 2.1, Colin D Funk
MGI accession ID: MGI:6119506
Generation method: Targeted
Attributes: Inserted expressed sequence
Synonyms: COX-2COX-1; Ptgs2Ptgs1
Marker symbol: Ptgs1
Marker name: prostaglandin-endoperoxide synthase 1
Marker synonyms: Cox1; Cox-1; COX3; Cox-3; cyclooxygenase 1; PCOX1; PES-1; PGG/HS; PGHS1; Pghs-1; PHS1; PTGHS
Chromosome: 2
Strain of origin: C57BL/6
Molecular note: The genomic region containing exons 3-10 was replaced with a Ptgs2 gene fragment containing exons 2-10 and a floxed neo cassette. Cre mediated recombination removed the neo cassette. qPCR analysis confirmed the expression of a fused Ptgs1-Ptgs2 transcript in multiple tissues.