FVB/NJ-Rasal2^{Tn(pb-Act-RFP)1Xwu}/J

Stock number: 030427
Product name: Rasal2^PB
Research areas: Diabetes and Obesity Research, Internal/Organ Research, Metabolism Research, Research Tools

Description

Homozygous Rasal2^PB mice express only 10% of normal RAS protein activator like 2 mRNA levels. They show decreased adiposity and resistance to high fat diet-induced obesity and other metabolic disorders.

Detailed description

Genome scans have associated the RASAL2 (RAS protein activator like 2) gene with increased body mass index in humans. Further studies suggest the gene promotes adipogenesis and may play a role in the development of obesity and related metabolic disorders.

This hypopmorphic mutant allele decreases expression of the mouse Rasal2 gene by more than 90% in various tissues. Homozygotes have normal viability, but fertility has not been assessed. They show decreased adiposity and resistance to high fat diet-induced obesity and other metabolic disorders such as insulin resistance and glucose intolerance.

On a normal chow diet, male homozygous mice show a modest decrease in body weight starting at 6 weeks of age. This decrease in body weight is seen at 8 weeks of age in females. Nuclear magnetic resonance (NMR) analysis reveals that homozygotes have significantly less fat mass, with only a subtle change in lean mass.

Male homozygotes fed a high fat diet have a significantly lower body weight from the age of 5 weeks. They display comparable food intake, locomotor activity, and respiratory exchange rate to wildtype control mice. Their energy expenditure is significantly higher, however. They exhibit significantly enhanced glucose tolerance and insulin sensitivity. Serum triglycerides and cholesterol levels are significantly lower. Homozygotes are also protected from high fat diet-induced hepatic steatosis. Deficiency in Rasal2 abrogates high fat diet-induced M2 macrophage infiltration in white adipose tissue. Adipogenesis is impaired both in vivo and in vitro.

Red fluorescent protein (RFP), incorporated in the mutation construct, is expressed from an actin (Actb) promoter.

Development

A piggyBac (PB) transposon element derived from cabbage looper moth Trichoplusia ni was introduced to intron 3 of the mouse Rasal2 gene via pronuclear injection of FVB/NJ embryos.

Two circular plasmids, termed "donor" and "helper" were coinjected in circular forms into the pronuclei of FVB/NJ mouse embryos. The donor plasmid encodes the piggyBac transposon in which transposase sequences were replaced with a red fluorescent protein (RFP) reporter under the control of an Actb (β-actin) promoter. The helper plasmid, also expressed under the control of an Actb (β-actin) promoter, encodes piggyBac transposase lacking the terminal sequences required for transposition. RFP is flanked by transposon donor and transposase helper sequences in the final construct.

This line was created and maintained on an FVB/NJ genetic background by the donating laboratory.

Allele

Symbol: Rasal2^{Tn(pb-Act-RFP)1Xwu}
Name: transposon insertion 1, Xiaohui Wu
MGI accession ID: MGI:5897630
Generation method: Transposon induced
Attributes: Reporter; Hypomorph
Marker symbol: Rasal2
Marker name: RAS protein activator like 2
Marker synonyms: A330066M24Rik; NGAP
Chromosome: 1
Strain of origin: FVB/NJ
Expressed genes: RFP,Red Fluorescent Protein,coral
Site of expression: Red fluorescent protein is ubiquitously expressed from the actin (Actb) promoter.
Molecular note: A piggyBac (PB) transposon element derived from cabbage looper moth Trichoplusia ni is introduced to intron 3 of the gene. Its components were introduced by coinjection of mouse oocytes with circular piggyBac donor and helper plasmids. The donor plasmid contained the piggyBac transposon element in which the transposase sequence was replaced by a beta actin (Actb) promoter-driven red flourescent protein (RFP) reporter gene flanked by piggyBac-specific inverted terminal repeat sequences. The helper plasmid employs the Actb promoter to drive expression of a piggyBac transposase gene lacking the terminal inverted repeat sequences required for its transposition. The insertion contains the RFP expression unit flanked by transposon (donor) and transposase (helper) sequences. RFP is flanked by transposon donor and transposase helper sequences in the final construct. Expression of Rasal2 is decreased by more than 90% in some tissues.