Phenotypes associated with this allele

• Allele Symbol: Mc4r^tm1.1Fbz
• Allele Name: targeted mutation 1.1, Florian Bolze
• Allele ID: MGI:5703936
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Mc4r^tm1.1Fbz/Mc4r^tm1.1Fbz	involves: 129S4/SvJae * C57BL/6 * C57BL/6J * C57BL/6NTac	MGI:5707333
ht2	Mc4r^tm1.1Fbz/Mc4r^+	involves: 129S4/SvJae * C57BL/6 * C57BL/6J * C57BL/6NTac	MGI:5707334

Genotype
MGI:5707333

hm1

• Allelic Composition: Mc4r^tm1.1Fbz/Mc4r^tm1.1Fbz
• Genetic Background: involves: 129S4/SvJae * C57BL/6 * C57BL/6J * C57BL/6NTac

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

growth/size/body

decreased lean body mass ( J:225022 )

• when singly housed under SPF conditions, homozygotes of both sexes show reduced abdominal lean mass relative to wild -type controls

increased lean body mass ( J:225022 )

♂ • at 25-28 weeks of age, only male homozygotes show a higher abdominal lean mass than age-matched heterozygous and wild-type littermates, indicating a sex-specific difference in lean mass

increased body weight ( J:225022 )

• at ~6-7 weeks of age, homozygotes of both sexes are obviously heavier than wild-type controls

obese ( J:225022 )

• homozygotes become obese by 9 weeks of age

• at >6 months of age, male and female homozygotes weigh 70% and 100% more, respectively, than wild-type controls

• obesity was not ameliorated during a 7-day gentamicin treatment of male homozygotes at the age of 36 weeks

• similarly, no reduction of obesity was observed during a 19-day amikacin treatment of female homozygotes at the age of 42 weeks

increased body length ( J:225022 )

• at ~20 weeks of age, homozygotes of both sexes show a ~10% increase in snout-to-anus distance relative to wild -type controls

behavior/neurological

polyphagia ( J:225022 )

• at ~20 weeks of age, homozygotes of both sexes display hyperphagia resulting in an increased energy intake and energy assimilation (defined as the amount of energy resorbed by the intestine epithelium)

• however, assimilation efficiency is unaffected, indicating normal nutrient resorption

adipose tissue

increased abdominal fat pad weight ( J:225022 )

• analysis of abdominal body composition of dead mice at 25-28 weeks of age revealed that increased body weight is mainly due to an increase in visceral fat mass

homeostasis/metabolism

increased energy expenditure ( J:225022 )

• at 9 weeks of age, obese homozygotes of both sexes display significantly increased daily energy expenditure relative to wild-type controls, as shown by indirect calorimetry

• however, no difference in metabolic rate is noted in young pre-obese homozygotes at 6 weeks of age

• respiratory quotient is normal

impaired glucose tolerance ( J:225022 )

• at ~20 weeks of age, homozygotes of both sexes display impaired glucose tolerance

• males are more affected than females

Genotype
MGI:5707334

ht2

• Allelic Composition: Mc4r^tm1.1Fbz/Mc4r⁺
• Genetic Background: involves: 129S4/SvJae * C57BL/6 * C57BL/6J * C57BL/6NTac

growth/size/body

increased body weight ( J:225022 )

• at ~6-7 weeks of age, heterozygotes show an increase in body weight that is intermediate between that of homozygous mutant and wild-type littermates

increased body length ( J:225022 )

• at ~20 weeks of age, heterozygotes of both sexes show a ~5% increase in snout-to-anus distance relative to wild-type controls

adipose tissue

increased abdominal fat pad weight ( J:225022 )

• analysis of abdominal body composition of dead mice at 25-28 weeks of age revealed that heterozygotes show a gain in fat mass intermediate to that observed in homozygous mutant and wild-type littermates

homeostasis/metabolism

homeostasis/metabolism phenotype ( J:225022 )

N • heterozygotes display normal energy intake and assimilation relative to wild-type controls