B6.129S-Eif2b5^tm1Oels/J

Stock number: 040869
Product name: Eif2b5^R132H
Strain synonyms: Eif2b5(R132H/R132H)
Research areas: Mouse/Human Gene Homologs, Neurobiology Research

Description

The Eif2b5^R132H knock-in mice carry the amino acid substitution of arginine to histidine at position 132 (R132H), resembling a mutation found in human patients (R136H) with leucoencephalopathy with vanishing white matter. These homozygous Eif2b5^R132H mice may be useful for studying eIF2B function during development and VWM disease.

Detailed description

The Eif2b5^R132H knock-in mice carry the amino acid substitution of arginine to histidine at position 132 (p.Arg132His) in the eukaryotic translation initiation factor 2B, subunit 5 epsilon (Eif2b5) gene. The mutation corresponds to the clinically significant human R136H mutation found in patients with leukoencephalopathy, childhood ataxia with central nervous system hypomyelination (CACH)/vanishing white matter (VWM) disease when homozygous. The homozygous mutation reduces eIF2B enzymatic activity in the brain by ~20%, dysregulating global mRNA translation and causing a wide range of cellular dysfunctions, primarily affecting glial cells, which leads to white matter abnormalities and motor dysfunctions. In addition, donating investigators showed the dysregulated gene expression, mitochondrial malfunction, reduced ATP levels, leading to metabolic stress, and hypersensitivity to oxidative stress in these mice. Under normal conditions, mutant mice exhibit normal lifespan and fertility and do not develop severe clinical symptoms. However, they show a 10-25% reduction in body weight compared to wild-type littermates. Motor deficits become evident only under challenging conditions (such as during the rotarod performance test). These Eif2b5^R132H mice may be useful for studying eIF2B function during development and VWM disease.

Development

The targeting vector consists of a floxed neo cassette in intron 2 and a modified exon 3 of the endogenous eukaryotic translation initiation factor 2B, subunit 5 (Eif2b5) gene. The modified exon 3 carry two point mutations: (i) c.G2723A substitution, resulting in amino acid substitution of arginine to histidine at position R132 of the encoded protein (e.g., R132H mutation, corresponding to the human R136H mutation; c.G2723A); and (ii) a silent mutation designed to generate a unique SalI site to enable genotyping (c.T2756C). The mutations were generated by PCR, cloned into pcDNA3.1 plasmid, and assembled into a targeting vector containing the mutated 3' arm, the Neo cassette, and a 5' arm. The construct was electroporated into 129S/SvEv-derived embryonic stem (ES) cells iTL1 and screened by Southern blot analysis. Two correctly targeted ES cells were injected into recipient blastocysts. The resulting chimeric animals were crossed to C57BL/6J mice to generate germline founders. Founder mice carrying the Eif2b5^R132H mutation were intercrossed to produce homozygous mice. The mice were backcrossed to C57BL/6JOlaHsd for more than 20 generations by the donating laboratory. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.

Allele

Symbol: Eif2b5^tm1Oels
Name: targeted mutation 1, Orna Elroy-Stein
MGI accession ID: MGI:5306369
Generation method: Targeted
Attributes: Humanized sequence
Synonyms: Eif2b5^R132H; Eif2b5^tm1Itl
Marker symbol: Eif2b5
Marker name: eukaryotic translation initiation factor 2B, subunit 5 epsilon
Marker synonyms: CACH; CLE; EIF-2B; EIF2Bepsilon; LVWM; VWM5
Chromosome: 16
Strain of origin: 129S/SvEv
Molecular note: Exon 3 was replaced with a floxed neo cassette and a modified exon 3 in which a nucleotide substitutions (c.G2723A and a silent mutation generating a novel and unique Sal1 restriction site to facilitate genotyping) result in the amino acid substitution of histidine for arginine at position 132 (R132H), mimicking a mutation found in human patients suffering from leucoencephalopathy with vanishing white matter.