B6.Cg-Crb1^rd8 Jak3^m1J/BocJ

Stock number: 005558
Product name: retinal vascularization 3 model, rnv3

Strain synonyms: rnv3, NRV2 mice
Research areas: Cell Biology Research, Developmental Biology Research, Immunology, Inflammation and Autoimmunity Research, Internal/Organ Research, Mouse/Human Gene Homologs, Sensorineural Research

Description

This strain, which is homozygous for both of Crb1^rd8 and Jak3^m1J, has a more severe phenotype than Crb1^rd8 homozygotes lacking the Jak3^m1J mutation, with early-onset multifocal depigmented retinal lesions and photoreceptor loss. The phenotype of the combined genotype provides the model retinal vascularization 3 (rnv3).

Detailed description

The ocular phenotype of Crb1^rd8 homozygotes is increased in severity by the additional homozygosity of Jak3^m1J. Double homozygotes develop multifocal depigmented retinal lesions by 18 days of age which expand in size and by 25 days of age fluorescein leakage is also found. This increases with age and is associated with progressive photoreceptor degeneration and accompanying deterioration of electroretinogram responses. At 8 weeks of age, both scotopic and photopic electroretinogram responses are slightly reduced and by 8 months, this reduction is severe. Neovessels extend from the deep retinal vascular plexus in the outer plexiform layer through the outer retina between 17 and 25 days of age and balloon-like neovessel structures are found in the photreceptor cell layer. By 2 months aberrant vessels are found to span from the retinal pigment epithelium to the inner nuclear layer, the outer nuclear layer is thinner than normal, and photoreceptor cell degeneration occurs where this vasculature disrupts the retina. In addition to the ocular phenotype, these double homozygotes have small thymi and spleens due to homozygosity of the Jak3^m1J mutation and can develop pneumocystis and die by 6 months of age. Sublines were bred from this strain that has only the Crb1^rd8 mutation (see Stock No. 031586) or only the Jak3^m1J mutation (see Stock No. 031587).

Update, November, 2024:
This is a special strain for retinal neovascularization (rnv3). Any outcross to another strain may result in the loss of the rnv3 phenotype. Maintenance of the current genetic background is recommended.

The retinal neovascularization mutation was first identified in B6;129-Crhr1^tm1Klee/J animals (Stock No. 004454) by outcrossing phenotypic mutants to C57BL/6J (Stock No. 000664) and intercrossing to select mice with the most severe phenotype for 5 generations (N5). Mice with the most severe rnv3 phenotype were chosen to breed/maintain their colony. During the process of development, some other genes were likely fixed in the background to enhance the rnv3 phenotype.

In order to preserve the current genetic background, the donating investigator cryopreserved the strain as embryos rather than sperm. If cryorecovery from frozen sperm is necessary, and in the absence of females from the colony (Stock No. 005558), recoveries using C57BL/6NJ females (Stock No. 005304), which retain the Crb1^rd8 allele, would be preferable to recoveries with C57BL/6J females (Stock No. 000664), which do not carry the Crb1^rd8 allele.

Development

Fundus retinal depigmentation spots were identified in the strain B6;129-Crhr1^tm1Klee/J (Stock No. 004454). These mice were backcrossed once to C57BL/6J and the resulting F1 hybrids intercrossed. From that population mice lacking the Crhr1^tm1Klee mutation but expressing the retinal depigmentation spots were selected and this ocular phenotype was moved onto the C57BL/6J background by repeated rounds of backcross-intercross breeding until NE5 when the strain was intercrossed for homozygosity of both Crb1^rd8 and Jak3^m1J and maintained by sibling intercrossing.

The Jak3^m1J allele incorporates a spontaneous G to A missense mutation in exon 24 of the mouse Jak3 (Janus kinase 3) gene that changes codon 1081 from CGG (arginine) to CAG (glutamine). This occurred in a gene sequence already containing an A to C transversion in codon 1032 common in at least 27 inbred strains, which causes an amino acid change from serine to arginine (AGC to CGC).

The Crb1^rd8 mutation incorporates a single base deletion of a C (G on forward strand) at coding nucleotide 3481 of the mouse Crb (crumbs family member 1, photoreceptor morphogenesis associated) gene. This deletion causes a frame shift and a premature stop codon that truncates the transmembrane and cytoplasmic domain of the protein after amino acid 1207. This mutation has been found to be present in all sublines of C57BL/6N and in C57BL/6ByJ, but not in any C57BL/6J subline.

In 2023, A 48 SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. Results suggest an incomplete backcross to C57BL/6, with 129 allelic segregation on multiple chromosomes. The C57BL/6 contribution is likely to involve a mix of C57BL/6J and C57BL/6NJ substrains.

Allele

Symbol: Crb1^rd8
Name: retinal degeneration 8
MGI accession ID: MGI:2676366
Generation method: Spontaneous
Synonyms: Crb1^6N; nmf144; Rd8^-
Marker symbol: Crb1
Marker name: crumbs family member 1, photoreceptor morphogenesis associated
Marker synonyms: 7530426H14Rik; A930008G09Rik; CRB1-A; CRB1-B; CRB1-C; LCA8; RP12
Chromosome: 1
Strain of origin: C57BL/6By or C57BL/6N
Molecular note: The mutation in the rd8 mouse has been identified as a single base deletion of a C (G on forward strand) at coding nucleotide 3481 in the gene. This deletion causes a frame shift and a premature stop codon that truncates the transmembrane and cytoplasmic domain of the protein after amino acid 1207. This mutation has been found to be present in all sublines of C57BL/6N and in C57BL/6ByJ, but not in any C57BL/6J subline. It occurred sometime between transfer of mice from JAX to NIH, in 1951, and from NIH to Donald Bailey, in 1961.

Allele

Symbol: Jak3^m1J
Name: mutation 1, Jackson
MGI accession ID: MGI:6108882
Generation method: Spontaneous
Attributes: Not Specified
Marker symbol: Jak3
Marker name: Janus kinase 3
Marker synonyms: JAK-3; JAK3_HUMAN; JAKL; LJAK; L-JAK; RATJAK3
Chromosome: 8
Strain of origin: B6;129-Crhr1^tm1Klee/J
Molecular note: This spontaneous G to A transition in exon 24 results in a missense mutation, changing codon 1081 from CGG, arginine, to CAG, glutamine. This occurred in a gene sequence already containing the A to C transversion in codon 1032 common in at least 27 inbred strains, which causes an amino acid change from serine to arginine.