B6.CAST-(D17Mit19-D17Mit50)Bksr/J

Stock number: 025743
Strain synonyms: B6.CAST-17.1
Research areas: Metabolism Research

Description

B6.CAST-17.1 mice contain a 40.1 Mb congenic interval on Chr 17 linked to macronutrient-specific intake, total kilocalorie intake, and increased physical activity. They may be useful when studying genetic contributions and interactions among genes controlling carbohydrate vs. fat selection and energy intake.

Detailed description

These B6.CAST-17.1 mice are congenic for a segment of Chr 17 from D17Mit19 (4.8 Mb) to D17Mit50 (45.4 Mb) from the CAST/Ei (CAST) donor strain on the C57BL/6J background. This segment contains three significant quantitative trait loci (QTL) for macronutrient-specific intake (Mnic1), total kilocalorie intake (Kcal2), and total food volume (Tfv1). In a two-diet-choice paradigm, mice homozygous for the CAST congenic segment consumed, per body weight, significantly more carbohydrate/protein calories (30%), total calories (9%), and total grams of food (15%), and significantly less fat/protein calories (15%) compared with wild-type B6 littermates. (B6 x B6.CAST-17.1)F2 homozygotes also exhibited 22% higher spontaneous physical activity levels and significantly increased voluntary wheel-running activity compared with littermate wild-type B6.

Development

The original congenic strain, B6.CAST-17 was developed by backcrossing (CASTXB6)F1 male mice to B6 females for six generations using a marker-assisted, speed congenic approach. In this manner, a segment of CAST donor DNA from proximal chromosome 17 was introgressed to the B6 genome. This congenic segment contains the Mnic1/Kcal2/Tfv1 QTL interval. The B6.CAST-17 congenic strain was then bred back to B6 to shorten the congenic interval further, and was found to retain the nutrient intake traits of the original congenic strain. The B6.CAST-17.1 mice are congenic for a segment of Chr 17 from D17Mit19 (4.8 Mb) to D17Mit50 (45.4 Mb) from the CAST donor strain on the B6J background. The CAST DNA boundaries in this congenic segment were also established using SNP markers rs49640908 (proximal at 3.19 Mb) and rs48762654 (distal at 45.73 Mb). Upon arrival, these mice were bred to C57BL/6J mice (Stock No. 000664) for one generation to establish the colony. The rederived mice were then typed for the specific MIT markers defining the congenic interval to determine if any recombination events had occurred.

Allele

Symbol: Kcal2^CAST/EiJ
Name: CAST/EiJ
MGI accession ID: MGI:2449301
Generation method: QTL
Marker symbol: Kcal2
Marker name: kilocalorie 2
Chromosome: 17
Strain of origin: CAST/EiJ
Molecular note: This allele confers increased calorie intake over a 10 day period compared to C57BL/6J.

Allele

Symbol: Mnic1^CAST/EiJ
Name: CAST/EiJ
MGI accession ID: MGI:2449294
Generation method: QTL
Marker symbol: Mnic1
Marker name: macronutrient intake, carbohydrate 1
Chromosome: 17
Strain of origin: CAST/EiJ
Molecular note: This allele confers increased carbohydrate/protein (C/P) kcal intake compared to C57BL/6J.

Allele

Symbol: Tfv1^CAST/EiJ
Name: CAST/EiJ
MGI accession ID: MGI:3774625
Generation method: QTL
Marker symbol: Tfv1
Marker name: total food volume 1
Chromosome: 17
Strain of origin: CAST/EiJ
Molecular note: This allele confers increased total food volume intake compared to C57BL/6J.

Allele

MGI accession ID: MGI:90840
Marker symbol: D17Mit50
Marker name: DNA segment, Chr 17, Massachusetts Institute of Technology 50
Chromosome: 17

Allele

MGI accession ID: MGI:90806
Marker symbol: D17Mit19
Marker name: DNA segment, Chr 17, Massachusetts Institute of Technology 19
Chromosome: 17