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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID
Fosbtm1Meg
targeted mutation 1, Michael E Greenburg
MGI:1857395
Summary 4 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
Fosbtm1Meg/Fosbtm1Meg either: (involves: 129S4/SvJae * 129X1/SvJ) or (involves: 129S4/SvJae * 129X1/SvJ * BALB/c) MGI:3653349
hm2
Fosbtm1Meg/Fosbtm1Meg involves: 129S4/SvJae * 129X1/SvJ MGI:3653339
hm3
Fosbtm1Meg/Fosbtm1Meg involves: 129S4/SvJae * 129X1/SvJ * BALB/c MGI:3653352
ht4
Fosbtm1Meg/Fosb+ involves: 129S4/SvJae * 129X1/SvJ * BALB/c MGI:3653353


Genotype
MGI:3653349
hm1
Allelic
Composition
Fosbtm1Meg/Fosbtm1Meg
Genetic
Background
either: (involves: 129S4/SvJae * 129X1/SvJ) or (involves: 129S4/SvJae * 129X1/SvJ * BALB/c)
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fosbtm1Meg mutation (1 available); any Fosb mutation (15 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• young homozygous males display defective nurturing behavior illustrated by impaired pup retrieval compared to wild-type males
• majority of pups die within 1 to 2 days of birth regardless of their genotype
• homozygous pups will survive if fostered by wild-type or heterozygous females
• Background Sensitivity: if homozygous females are mated to homozygous, heterozygous or wild-type males on a 129 background, 0-1 pups on average survive to weaning regardless of pup genotype; if homozygous males are mated to heterozygous or wild-type females, 3-5 pups survive to weaning regardless of pup genotype
• Background Sensitivity: if homozygous females are mated to homozygous, heterozygous or wild-type males on 129/B6 background, only 1-2 pups survive to weaning regardless of pup genotype; if homozygous males are mated to heterozygous or wild-type females, 7-9 pups survive to weaning regardless of genotype
• homozygous females do not nurse their pups
• if 3 pups are removed from the cage then replaced shortly after, homozygous females take 50 times longer to retrieve the first pup compared to wild-type or heterozygotes and only 50% retrieve even one pup

growth/size/body
• homozygotes are about ~10% smaller than wild-type




Genotype
MGI:3653339
hm2
Allelic
Composition
Fosbtm1Meg/Fosbtm1Meg
Genetic
Background
involves: 129S4/SvJae * 129X1/SvJ
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fosbtm1Meg mutation (1 available); any Fosb mutation (15 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• 2-3 month old mutant mice show a significant delay in development of tolerance to motor seizures compared to wild-type mice; repeated ECS treatment does eventually result in a significant reduction in seizure duration, to wild-type levels by day 6 of treatment

nervous system
• 2-3 month old mutant mice show a significant delay in development of tolerance to motor seizures compared to wild-type mice; repeated ECS treatment does eventually result in a significant reduction in seizure duration, to wild-type levels by day 6 of treatment
• in layer II/III pyramidal cells, repeated ECS treatments does not alter 25 um NMDA-induced inward current but currents in wild-type cells are significantly enhanced in brain slices from 2-3 month old mutants




Genotype
MGI:3653352
hm3
Allelic
Composition
Fosbtm1Meg/Fosbtm1Meg
Genetic
Background
involves: 129S4/SvJae * 129X1/SvJ * BALB/c
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fosbtm1Meg mutation (1 available); any Fosb mutation (15 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• mutants display a significant decrease (41.5%) in REM sleep during lights-on periods; there is a significant decrease (31.5%) in REM sleep during the lights-out period compared to wild-type




Genotype
MGI:3653353
ht4
Allelic
Composition
Fosbtm1Meg/Fosb+
Genetic
Background
involves: 129S4/SvJae * 129X1/SvJ * BALB/c
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fosbtm1Meg mutation (1 available); any Fosb mutation (15 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• mice show fewer numbers of REM sleep bouts than wild-type





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last database update
01/12/2022
MGI 6.17
The Jackson Laboratory