cellular phenotype

• decreased mitochondrial DNA content
  • in unstimulated interscapular brown adipose tissue
  (MGI Ref ID J:213153)

• decreased mitochondrial number
  • with poorly organized cristae in unstimulated interscapular brown adipose tissue
  (MGI Ref ID J:213153)

• abnormal cellular respiration
  • reduced basal in interscapular brown adipose tissue
  (MGI Ref ID J:213153)

growth/size/body region phenotype

• decreased body fat mass
  (MGI Ref ID J:213153)

• decreased body length
  (MGI Ref ID J:213153)

• decreased body weight
  • at all ages
  (MGI Ref ID J:213153)

• decreased lean body mass
  (MGI Ref ID J:213153)

homeostasis/metabolism phenotype

• abnormal oxygen consumption
  (MGI Ref ID J:213153)

• impaired adaptive thermogenesis
  • precipitous drop in body temperature following exposure to cold
  (MGI Ref ID J:213153)

• improved glucose tolerance
  (MGI Ref ID J:213153)

adipose tissue phenotype

• abnormal interscapular fat pad morphology
  • whitening in mice older than 6 months with increased size of the tissue, a switch from multilocular to unilocular morphology, and increased lipid content
  (MGI Ref ID J:213153)
  • 3 week old mice fed a high-fat diet exhibit loss of normal brown adipocyte morphology unlike wild-type mice
  (MGI Ref ID J:213153)

• decreased brown fat lipid droplet number
  • in the interscapular brown adipose tissue of mice older than 6 months
  (MGI Ref ID J:213153)

• increased brown fat cell lipid droplet size
  • in the interscapular brown adipose tissue of mice older than 6 months
  (MGI Ref ID J:213153)

• increased interscapular fat pad weight
  • in mice older than 6 months
  (MGI Ref ID J:213153)
  • Normal - however, juvenile mice exhibit normal sized brown adipose tissue depots
  (MGI Ref ID J:213153)

• abnormal brown adipose tissue morphology
  • pale axillary and cervical brown adipose tissue depots
  (MGI Ref ID J:213153)
  • Normal - however, tissue mass is not altered
  (MGI Ref ID J:213153)

• abnormal brown adipose tissue thermogenesis
  • Normal - however, diet-induced thermogenesis is normal
  (MGI Ref ID J:213153)
  • precipitous drop in body temperature following exposure to cold
  (MGI Ref ID J:213153)

• decreased body fat mass
  (MGI Ref ID J:213153)

• whitened brown adipose tissue morphology
  • whitening in mice older than 6 months with increased size of the tissue, a switch from multilocular to unilocular morphology, and increased lipid content
  (MGI Ref ID J:213153)

cellular phenotype

• decreased adipocyte glucose uptake
  • glucose uptake is reduced in subcutaneous fat (79% decrease) and visceral fat (53% decrease) after 6 weeks on high fat diet as compared to controls
  (MGI Ref ID J:208683)

growth/size/body region phenotype

• increased susceptibility to weight gain
  • mice exhibit increased weight gain after 16 weeks on high-fat, high-carbohydrate diet relative to control mice
  (MGI Ref ID J:208683)

hematopoietic system phenotype

• increased macrophage cell number
  • subcutaneous adipose tissue from mice following 6 weeks on high fat diet has increased numbers of CD11b+F4/80+ macrophages, but macrophage numbers in visceral adipose tissue and spleen are unchanged
  (MGI Ref ID J:208683)

homeostasis/metabolism phenotype

• increased liver triglyceride level
  • increased liver tryglycerides are observed in mice after 6 weeks on high fat diet as compared to controls
  (MGI Ref ID J:208683)

• increased respiratory quotient
  • mice exhibit an increased respiratory exchange ratio (RER), but no increase in O₂ consumption
  (MGI Ref ID J:208683)

• increased circulating insulin level
  • increased fasting plasma insulin levels (55%) in mice after 6 weeks on high fat diet
  (MGI Ref ID J:208683)

• insulin resistance
  • a reduced glucose infusion rate (64% of controls) is observed in mice after 6 weeks on high fat diet
  (MGI Ref ID J:208683)
  • clamped insulin levels do not increase as much as controls in mice after 6 weeks on high fat diet
  (MGI Ref ID J:208683)
  • decreased whole body glucose uptake is observed in mice after 6 weeks on high fat diet
  (MGI Ref ID J:208683)

• abnormal oxygen consumption
  • unlike controls, mutant mice do not exhibit increased O₂ consumption following stimulation with a beta-adrenergic agonist
  (MGI Ref ID J:208683)

immune system phenotype

• increased macrophage cell number
  • subcutaneous adipose tissue from mice following 6 weeks on high fat diet has increased numbers of CD11b+F4/80+ macrophages, but macrophage numbers in visceral adipose tissue and spleen are unchanged
  (MGI Ref ID J:208683)

integument phenotype

• increased subcutaneous adipose tissue amount
  • subcutaneous fat mass from male mice after 16 weeks on high fat diet is increased to twice that of controls, epididymal and brown adipose tissue are unchanged
  (MGI Ref ID J:208683)

liver/biliary system phenotype

• increased liver triglyceride level
  • increased liver tryglycerides are observed in mice after 6 weeks on high fat diet as compared to controls
  (MGI Ref ID J:208683)

• hepatic steatosis
  • after 6 weeks on high fat diet
  (MGI Ref ID J:208683)

adipose tissue phenotype

• abnormal adipose tissue morphology
  • subcutaneous adipose tissue contains larger adipocytes and fewer smaller multiocular UCP1+ adipocytes relative to control mice following cold exposure
  (MGI Ref ID J:208683)
  • subcutaneous adipose tisse from mice following 6 weeks on high fat diet has increased numbers of CD11b+F4/80+ macrophages
  (MGI Ref ID J:208683)
  • subcutaneous adipose tissue from mice following 6 weeks on high fat diet has increased numbers of crown like structures, however, there are no changes in visceral (abdominal) fat
  (MGI Ref ID J:208683)

• increased fat cell size
  • subcutaneous adipocytes from male mice after 18 weeks on high fat diet exhibit a 33% increase in mean adipocyte area
  (MGI Ref ID J:208683)

• abnormal brown adipose tissue thermogenesis
  • subcutaneous adipocytes exhibit a blunted response to stimuli such as isoproterenol that induce a thermogenic gene program (beige adipocytes)
  (MGI Ref ID J:208683)

• decreased adipocyte glucose uptake
  • glucose uptake is reduced in subcutaneous fat (79% decrease) and visceral fat (53% decrease) after 6 weeks on high fat diet as compared to controls
  (MGI Ref ID J:208683)

• abnormal adipose tissue physiology
  • O₂ consumption is reduced in subcutaneous adipose pads, but not in brown adipose pads, at baseline (36% reduced) and following stimulation with a beta-adrenergic agonist (49% reduced)
  (MGI Ref ID J:208683)

• increased subcutaneous adipose tissue amount
  • subcutaneous fat mass from male mice after 16 weeks on high fat diet is increased to twice that of controls, epididymal and brown adipose tissue are unchanged
  (MGI Ref ID J:208683)

• abnormal adipose tissue distribution
  • subcutaneous fat mass is doubled as compared to controls after 16 weeks on high fat diet; epididymal and BAT masses are unchanged
  (MGI Ref ID J:208683)

• increased total body fat amount
  • body composition analysis after 16 weeks on high fat diet indicates increased fat mass with no change in lean body mass
  (MGI Ref ID J:208683)

normal phenotype

• no abnormal phenotype detected
  • mice are viable and fertile
  (MGI Ref ID J:208683)