Elmo1L/L conditional knockin mice express ELMO1 protein at 30% of wild type by transcribing from the unstable loxP-flanked 3’ UTR from mouse Fos. Following cre recombination, Elmo1 (Elmo1H/H) expression is regulated by the stable bovine growth hormone (bGH) 3’ UTR resulting in a 200% increase in expression over wild type. When combined with the Ins2Akita allele, Elmo1 expression modulates the incidence and severity of diabetic nephropathy and cardiomyopathy. This strain provides graded Elmo1 expression ranging from 30% (pre-cre) to 200% (post-cre) of wild type expression.
Dr. Nobuyo Maeda, University of North Carolina at Chapel Hill
Elmo1 (engulfment and cell motility 1) encodes part of a guanine nucleotide exchange factor for the Ras-related Clostridium botulinum C3 toxin substrate (Rac) and is required for phagocytosis of apoptotic cells and cell motility. Polymorphisms in Elmo1 are associated with susceptibility to diabetic nephropathy. In Elmo1 mutant mice the 3’ UTR is replaced with a loxP-flanked unstable 3’ UTR from the mouse protoconcogene Fos (Elmo1L) or the stable 3’ UTR from bovine growth hormone (bGH) (Elmo1H). Fos has a very short-lived mRNA, while bGH increases the half-life of Elmo1 mRNA. When combined with a strain expressing cre recombinase the unstable Fos 3’UTR is switched for the stable bGH 3’ UTR creating the high-expressing Elmo1H allele. Hypomorphic homozygous Elmo1L/L mice express ELMO1 protein at 30% of wildtype. Hypermorphic homozygous Elmo1H/H mice express ELMO1 protein levels at greater than 190% of wildtype.
When combined with a cre expressing strain and the Akita mutation, C57BL/6-Ins2Akita/J (Stock No. 003548), hypermorphic Elmo1H/H Ins2Akita/+ (HHA+) progeny develop severe dilated cardiomyopathy (16 weeks of age), as well diabetic nephropathy (after 24 weeks of age - albuminuria, glomerulosclerosis), which is more severe than with the Akita allele alone. Plasma glucose and insulin levels are not affected by Elmo1 expression. In addition, indices of reactive oxygen species (ROS) increase as Elmo1 expression increases. In contrast, hypermorphic (pre-cre) Elmo1L/L Ins2Akita/+ (LLA+) mice do not develop diabetic nephropathy or cardiomyopathy.
A targeting vector was designed to insert a loxP site followed by the unstable 3’ UTR from Fos, a neomycin resistance cassette with an MC1 promoter, a second loxP site, and the stable 3’ UTR from the bovine growth hormone into the 3’ UTR (downstream of exon 22) of the Elmo1 (engulfment and cell motility 1) gene. The construct was electroporated into C57BL/6 (Ingenious) embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were crossed to C57BL/6J females, and offspring were backcrossed to C57BL/6J for at least 10 generations. Upon arrival, mice were bred to C57BL/6J for at least one generation to establish the colony.
|Allele Name||targeted mutation 1, Masao Kakoki|
|Allele Type||Targeted (Hypomorph)|
|Gene Symbol and Name||Elmo1, engulfment and cell motility 1|
|Strain of Origin||C57BL/6|
|Molecular Note||The 3'UTR was replaced with A loxP site, unstbale mouse Fos 3'UTR, neomycin resistance cassette, loxP site and stable bovine GH 3'UTR. QRT-PCR confirmed reduced transcript expression in the kidney of 40 week old mice.|
When maintaining a live colony, these mice are bred by homozygote sibling matings.
When using the Elmo1L mouse strain in a publication, please cite the originating article(s) and include JAX stock #035489 in your Materials and Methods section.