C.129S4-Eif4ebp1^tm1Nso/J

Stock number: 031225
Product name: 4E-BP1 KO
Research areas: Cardiovascular Research, Diabetes and Obesity Research, Endocrine Deficiency Research, Internal/Organ Research, Metabolism Research, Research Tools

Description

Eif4ebp1 (4E-BP1) knock-out mice exhibit hypoglycemia, reduced adipose tissue and increased metabolic rate. They are suitable for use in applications related to studies of adipogenesis and energy homeostasis.

Detailed description

The targeted Eif4ebp1 gene encodes a translation repressor protein that binds the eukaryotic translation initiation factor 4E (eIF4E) to inhibit the eukaryotic initiation factor 4F (eIF4F) complex that directs the small ribosomal subunit to the 5' cap structure of mRNAs. These 4E-BP1 knock-out mice carry an allele in which the splice acceptor site and the first 57 nucleotides of exon 2 has been replaced by a PGK-neo cassette. Mice that are homozygous for the targeted mutation are viable and fertile. No gene product (protein) is detected by western blot analysis of interscapular brown adipose tissue, epididymal white adipose tissue, inguinal white adipose tissue, pancreas, liver, kidney, lung, muscle, heart, testis, colon, spleen, and brain. Approximately 15% of homozygotes exhibit decreased blood glucose levels. Male homozygotes exhibit an approximately 60% reduction in circulating leptin levels and an increased (approximately 15%) metabolic rate. At 9 to 10 weeks of age, male homozygotes are approximately 91% body weight of wildtype controls. Male homozygotes develop increased multilocular adipocytes in inguinal and retroperitoneal white adipose tissue. Homozygotes, at 10 to 12 months of age, have reduced adipose tissue mass and white adipose tissue weight.

24-month-old "4E-BP1/4E-BP2" double knockout mice (JAX Stock Numbers 031225 and 031507), on the congenic BALB/c background, exhibit higher muscle mass (due to reduced lean mass loss: 6% double KO mice and 20% in wildtype) and protein synthesis in muscle tissue, compared to wildtype controls.

Development

A targeting vector containing a PGK-neo cassette (pMC1-Neo) was used to disrupt the splice acceptor site and the first 57 nucleotides of exon 2. The construct was electroporated into 129S4/SvJae-derived J1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into BALB/c blastocysts. The resulting chimeric animals were tested for germline transmission. The mice were then backcrossed to BALB/cAnNCrl for seven generations. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize BALB/cByJ oocytes (Stock No. 001026).

Allele

Symbol: Eif4ebp1^tm1Nso
Name: targeted mutation 1, Nahum Sonenberg
MGI accession ID: MGI:2177923
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: 4E-BP1 KO; Eif4ebp1-
Marker symbol: Eif4ebp1
Marker name: eukaryotic translation initiation factor 4E binding protein 1
Marker synonyms: 4EBP1; 4E-BP1; BP-1; PHAS-I
Chromosome: 8
Strain of origin: 129S4/SvJae
Molecular note: The splice acceptor site and the first 57 nucleotides of exon 2 were replaced with the neomycin-resistance gene. The disrupted portion of exon 2 encodes amino acids 47 to 66, which encompasses the binding site for EIF4E.