B6.129-Pcsk9^tm1.1Prat/J

Stock number: 039064
Product name: Pcsk9^flox
Research areas: Cardiovascular Research, Metabolism Research, Research Tools

Description

Pcsk9^floxed mice possess loxP sites flanking the proximal promoter region and exon 1 of the Pcsk9 gene. These mice may be useful for studying tissue-specific deletion of Pcsk9 in lipid metabolism.

Detailed description

Pcsk9 codes for proprotein convertase subtilisin/kexin type 9, which is responsible for regulation of cholesterol levels. PCSK9 is highly expressed in hepatocytes and secreted in plasma. Circulating PCSK9 binds cell surface low-density lipoprotein receptors and promotes the internalization of the complex and its degradation in the lysosomal pathway. Mutations in this gene are associated with familial hypo- and hypercholesterolemia and PCSK9 is a target for cholesterol-lowering therapies. These Pcsk9^flox mice carry a conditional allele with loxP sites flanking the proximal promoter and exon 1 of the Pcsk9 gene.

Mice homozygous for this floxed allele are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have the proximal promoter sequence and exon 1 deleted in the cre-expressing tissues. This deletion results in a functionally null allele. The donating investigator bred these floxed mice to a germline Cre-recombinase line (CMV-Cre) on a C57BL/6 background and confirmed there was no detectable Pcsk9 mRNA in liver or other tissues tested. These Pcsk9^flox mice may be useful for studying the role of PCSK9 in cholesterol metabolism and atherosclerosis.

Development

The Pcsk9^flox allele was generated using a targeting vector composed of loxP sites flanking the proximal promoter and exon 1 of the proprotein convertase subtilisin/kexin type 9 (Pcsk9) gene. The target construct also contained an FRT-flanked neomycin cassette. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells. Targeted ES cells were injected into recipient blastocysts. The resulting chimeric mice were bred with C57BL/6 to establish germline transmission. Progeny were crossed to Flp-recombinase mice (Stock No. 003946) to excise the neo cassette. The Flp-expressing transgene was removed through selective breeding. The resulting heterozygous Pcsk9^flox/+ mice, with neo cassette removed and floxed promoter/exon 1 intact, were backcrossed to C57BL/6J for at least 14 generations by the donating laboratory. Upon arrival at The Jackson Laboratory, 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: Pcsk9^tm1.1Prat
Name: targeted mutation 1.1, Annik Prat
MGI accession ID: MGI:4943284
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Pcsk9
Marker name: proprotein convertase subtilisin/kexin type 9
Marker synonyms: FH3; FHCL3; HCHOLA3; LDLCQ1; NARC1; NARC-1; PC9
Chromosome: 4
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: The proximal promoter and exon 1 were flanked by loxP sites and an FRT flanked neomycin selection cassette was inserted just downstream of the loxP site in intron 1. The neomycin selection cassette was subsequently excised by flp recombinase expressionafter crossing to Gt(ROSA)26Sor mice.