B6.129S6(Cg)-Ppp1r15b^tm1.1Deco/J

Stock number: 040748
Product name: CReP^loxP
Strain synonyms: Ppp1r15b^loxP
Research areas: Cell Biology Research, Research Tools

Description

The CReP^loxP allele has loxP sites flanking the exon 2 of the Ppp1r15b gene. These mice may be useful for studying the effects of translational regulation on the attenuation of the integrated stress response (ISR).

Detailed description

The CReP^loxP allele has loxP sites flanking the exon 2 of the protein phosphatase 1, regulatory subunit 15B (Ppp1r15b) gene. Also called CReP (constitutive repressor of eIF2α phosphorylation), Ppp1r15b encodes a subunit of the eukaryotic translation initiation factor 2A (eIF2α) phosphatase complex that plays a role in the regulation of the integrated stress response (ISR). During the ISR, phosphorylation of eIF2α by stress-specific kinases helps restore cellular homeostasis following exposure to environmental stresses. CReP promotes the dephosphorylation of eIF2α to regulate translation during the ISR. ISR activation has been observed in metabolic diseases including hepatic steatosis, steatohepatitis, and insulin resistance, but it remains unclear whether ISR contributes to the disease pathogenesis or represents an innate defense mechanism against metabolic stresses.

Homozygous mice are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exon 2 deleted in the Cre-expressing tissues. Deletion of exon 2 is expected to produce C-terminal truncated CReP protein devoid of PP1 and eIF2α binding domains. The truncated protein is incapable of promoting eIF2α dephosphorylation.

CReP^loxP/loxP mice were bred to Albumin-Cre mice (Stock No. 003574), with cre expression in the liver to produce CReP^LKO mice. CReP^LKO exhibit constitutive eIF2α phosphorylation in the liver. They are protected from high-fat diet-induced obesity, hepatic steatosis and insulin resistance, and they show browning of subcutaneous white adipose tissue, associated with elevated serum fibroblast growth factor 21 (FGF21) production.

Development

A targeting vector was designed to insert a loxP site in intron 1 of the of the protein phosphatase 1, regulatory subunit 15B (Ppp1r15b) gene, and a second loxP site was inserted 222 bp downstream of CReP coding region. The construct also contained an FRT-flanked neomycin resistance (neo) cassette. The construct was electroporated into 129S6/SvEvTac-derived-W4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts and the resulting chimeric mice were bred to C57BL/6J mice. Offspring were bred to Flp-expressing mice on an unknown background to remove the neo cassette. Resulting CReP^loxP mice, lacking the neo cassette, were backcrossed at least 10 generations to C57BL/6J mice (Stock No. 000664) by the donating investigator. 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.

Allele

Symbol: Ppp1r15b^tm1.1Deco
Name: targeted mutation 1, David E Cohen
MGI accession ID: MGI:8214689
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed)
Synonyms: CReP^LKO
Marker symbol: Ppp1r15b
Marker name: protein phosphatase 1, regulatory subunit 15B
Marker synonyms: 1810033K10Rik; C530022L24Rik; CReP; MSSGM2
Chromosome: 1
Strain of origin: 129S6/SvEvTac
Molecular note: A targeting vector was designed to insert a loxP site in intron 1 of the of the protein phosphatase 1, regulatory subunit 15B (Ppp1r15b) gene, and a second loxP site was inserted 222 bp downstream of CReP coding region. The construct also contained an FRT-flanked neomycin resistance (neo) cassette. Flp-recombinase removed the neo cassette.