Iba5^C57BL/6J
QTL Variant Detail

Summary

• QTL variant: Iba5^C57BL/6J
• Name: induction of brown adipocytes 5; C57BL/6J
• MGI ID: MGI:2670348
• QTL: Iba5 Location: Chr5:37686993-37687134 bp Genetic Position: Chr5, cM position of peak correlated region/allele: 20.2 cM
• QTL Note: genome coordinates based on the marker associated with the peak LOD score

Variant origin

• Strain of Specimen: C57BL/6J

Variant description

• Allele Type: QTL

Notes

Mapping and Phenotype information for this QTL, its variants and associated markers

J:83834

400 (C57BL/6J x A/J)F1 x A/J backcross animals were screened for loci at an average spacing of 20 cM to identify QTLs regulating the induction of Ucp1 and Ppargc1 in retroperitoneal white adipose tissue. Parental strain A/J exhibits strong Ucp1 inductionafter 7 days of cold exposure whereas parental strain C57BL/6J exhibits low Ucp1 induction.

Previously identified QTLs Iba1 (chr2), Iba2 (chr3), Iba3 (chr8), and Iba4 (chr19) were detected in this study, and a new QTL on mouse Chromosome 5, Iba5, was identified. All QTLs showed significant linkage to Ucp1 induction but only Iba2 showed strong linkage to both Ucp1 (LOD=6.6) and Ppargc1 (LOD=5.7) induction at D3Mit101 (49.7 cM).

Iba5 maps to 21 cM on mouse Chromosome 5 with peak linkage at D5Mit182 (P=6.3 x 10-7). Iba5 maps near Ppargc1. Ppargc1 was sequenced but no polymorphisms were uncovered between C57BL/6J and A/J. The 10kb of sequence flanking Ppargc1 also did not contain any polymorphisms.

Suggestive linkages to Ucp1 induction (P=.02) were detected at 40 cM (D4Mit116) on mouse Chromosomes 4 and at 19 cM (D10Mit214) on mouse Chromosome 10. These loci were more significantly linked to Ppargc1 induction (P=5.5 x 10-4 at D4Mit116) and (P=2.0 x 10-4 at D10Mit214).

J:101371

Linkage analysis was performed on a population of (C57BL/6J x A/J)F1 x A/J backcross animals to identify loci associated with regulation of Ucp1, Ppara, Ppargca1, and Dio2 (deiodinase type II) expression during cold-induced brown adipocyte induction. Animals were fed either a low fat (LF) or high fat (HF) diet and exposed to cold (5 degrees Celsius) for 7 days. Parental strain A/J displays significantly increased brown fat expression of Ucp1, Ppargc1a, Dio2, and Ppara mRNA after 7 days of cold exposure compared to C57BL/6J.

A previously identified QTL named Iba1 (induction of brown adipocytes 1) was detected in this study. Iba1 maps to 47.8 cM on mouse Chromosome 2 near D2Mit66. This locus is linked to cold-induced Dio2 expression on LF and HF diets andcold-induced Ppara expression on a HF diet. A novel locus named Iba6 (induction of brown adipocytes 6) mapped to 10 cM on mouse Chromosome 2 near D2Mit80. Iba6 is linked to cold-induced Dio2 expression on LF and HF diets.

Previously identified Iba2 (induction of brown adipocytes 2) was detected in this study at 48.2 cM on mouse Chromosome 3 near D3Mit101. This locus is linked to cold-induced Dio2 expression and cold-induced Ppara expression on a LF diet.

A novel locus linked to cold-induced Dio2 expression on a LF diet mapped to 49.5 cM on mouse Chromosome 4 near D4Mit175. This QTL is named Iba7 (induction of brown adipocytes 7).

Previously identified Iba5 (induction of brown adipocytes 5) was detected in this study at 24 cM on mouse Chromosome 5 nearD5Mit182. This locus is linked to cold-induced Dio2 expression and cold-induced Ppara expression on a LF diet.

Previously identified Iba3 (induction of brown adipocytes 3) was detected in this study at 37 cM on mouse Chromosome 5 near Ucp1. This locus is linked to cold-induced Dio2 expression on a LF diet and cold-induced Ppara expression on a HF diet.

A novel locus linked to cold-induced Dio2 expression and cold-induced Ppara expression on a LF diet mapped to 49 cM on mouse Chromosome 15 near D15Mit107. This QTL is named Iba8 (induction of brown adipocytes 8). Ppara is located at 48.8 cM and may be responsible for this locus.

Previously identified Iba4 (induction of brown adipocytes 4) was detected in this study at 20 cM on mouse Chromosome 19 near D19Mit86. This locus is linked to cold-induced Dio2 expression and cold-induced Ppara expression on a HF diet.

References

• Original: J:83834 Coulter AA, et al., Dietary fat interacts with QTLs controlling induction of Pgc-1alpha and Ucp1 during conversion of white to brown fat. Physiol Genomics. 2003 Jul 7;14(2):139-47
• All: 1 reference(s)