B6.129S2(Cg)-Ramp1^tm1.1Tsuj/WkinJ

Stock number: 031560
Product name: B6J.RAMP1-
Research areas: Cardiovascular Research, Cell Biology Research, Diabetes and Obesity Research, Immunology, Inflammation and Autoimmunity Research, Internal/Organ Research, Neurobiology Research, Research Tools, Sensorineural Research

Description

B6J.RAMP1- are C57BL/6J-congenic mice with the Ramp1 knock-out allele (exon 2 deleted). These mice may be useful for studying neuropeptide signaling in immunity (e.g., lymphangiogenesis, angiogenesis, injury), cardiovascular biology (e.g., blood pressure), neurobiology (e.g., migrane), obesity and cellular signaling pathways.

Detailed description

Calcitonin gene-related peptide (CGRP) receptor binding requires the receptor activity-modifying protein 1 (RAMP1). This Ramp1 knock-out allele has exon 2 deleted - the splicing of exons 1 to 3 creates a frameshift that results in a termination codon at the beginning of exon 3. RAMP1 knock-out blocks both alpha and beta CGRP signaling simultaneously.

C57BL/6J-congenic mice homozygous for the Ramp1 knock-out allele (B6J.RAMP1-/-) are viable and appear grossly normal. The donating investigator reports homozygotes were initially difficult to breed, but were breeding well by 2018. Homozygotes exhibit high blood pressure, with no changes in heart rate. Blood pressure is refractory to administration of some vasodilators (e.g., CGRP, acetylcholine or sodium nitroprusside).
When B6J.RAMP1-/- mice are used for distal limb fracture studies of complex regional pain syndrome, they exhibit attenuated allodynia and unweighting, no post-fracture warming response and increased IL-6 levels compared to similarly-treated wildtype controls [Guo et al. 2012 Mol Pain Mol 8:85].

Of note, LPS-induced inflammatory responses in BALB/c-congenic RAMP1-/- mice (BALBc.RAMP1-/-) reveal a transient and significant increase in the serum CGRP levels and high serum levels of pro-inflammatory cytokines compared with similarly-treated wildtype controls. To date (March 2018), the donating investigator has not tested this for B6J.RAMP1-/- mice.

Development

This RAMP1 knock-out allele was generated by Dr. Kazutake Tsujikawa (Osaka University). First, a targeting vector was designed to place a loxP site upstream of exon 2, and a loxP-flanked PGK-Neo^R cassette downstream of exon 2 of the receptor (calcitonin) activity modifying protein 1 locus (Ramp1) on chromosome 1. The construct was electroporated into 129S2/SvPas-derived D3 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts, and chimeric animals were bred with C57BL/6 mice for germline transmission of the Ramp1-flox allele. Ramp1-flox mice were bred with CAG-Cre transgenic mice (Tg(CAG-cre)13Miya; undisclosed genetic background) for germline deletion of the floxed sequences (exon2::PGK-Neo^R). The resulting RAMP1 knock-out allele (RAMP1-) has a single loxP site replacing exon 2. Dr. Tsujikawa maintained the RAMP1- colony by backcrossing to C57BL/6J for 12 generations (and the CAG-Cre transgene was also removed). In 2008, the C57BL/6J-congenic RAMP1- mice (B6J.RAMP1-) with black coat color were sent to Dr. Wade S. Kingery (Veterans Affairs Palo Alto Health Care System [VAPAHCS]). Dr. Kingery maintained the colony by backcrossing to C57BL/6J an additional eight generations, and then sent heterozygous males (black coat color) to The Jackson Laboratory Repository in 2018. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
Of note, the donating investigator reports that, at least once during backcrossing, a heterozygous female was bred to a C57BL/6J inbred male (thus the Y chromosome of the congenic strain is of C57BL/6J origin).

Allele

Symbol: Ramp1^tm1.1Tsuj
Name: targeted mutation 1, Kazutake Tsujikawa
MGI accession ID: MGI:3761144
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Ramp1
Marker name: receptor (calcitonin) activity modifying protein 1
Marker synonyms: 9130218E19Rik
Chromosome: 1
Strain of origin: 129S2/SvPas
Molecular note: This allele was generated by breeding mice heterozygous for Ramp1^tm1Tsuj with transgenic mice ubiquitously expressing cre recombinase. Exon 2 of the gene and the neomycin resistance cassette were removed, leaving behind a single loxP site. Upon deletion of exon 2, the splicing of exons 1 to 3 created a frameshift that resulted in the introduction of a termination codon at the beginning of exon 3. RT-PCR analysis of the thymus indicated there was no transcription of the wild-type gene.

Allele

Symbol: rd25
Name: retinal degeneration 25
MGI accession ID: MGI:7660543
Generation method: Spontaneous
Attributes: Not Specified
Marker symbol: rd25
Marker name: retinal degeneration 25
Chromosome: 14
Strain of origin: B6.129S2(Cg)-Ramp1^tm1.1Tsuj/WkinJ
Molecular note: This spontaneous mutation maps to Chr 14 between D14Mit62 and D14Mit234 where Rpgrip1 is the best candidate gene given the phenotype