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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		Fgf8tm1.1Mrt
targeted mutation 1.1, Gail R Martin
MGI:1857843
Summary 5 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
 		Fgf8tm1.1Mrt/Fgf8tm1.1Mrt involves: 129P2/OlaHsd MGI:2176813
ht2
 		Fgf8tm1.1Mrt/Fgf8tm1.2Mrt involves: 129P2/OlaHsd MGI:2176815
ht3
 		Fgf8tm1.1Mrt/Fgf8tm1.4Mrt involves: 129P2/OlaHsd MGI:2677315
cn4
 		Fgf8tm1.1Mrt/Fgf8tm1.4Mrt
Foxg1tm1M/Foxg1+ 		involves: 129P2/OlaHsd MGI:3654832
cn5
 		Fgf8tm1.1Mrt/Fgf8tm1.4Mrt
Foxg1tm1(cre)Skm/Foxg1+ 		involves: 129P2/OlaHsd MGI:3654834


Genotype
MGI:2176813
hm1
Allelic
Composition		 Fgf8tm1.1Mrt/Fgf8tm1.1Mrt
Genetic
Background		 involves: 129P2/OlaHsd
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fgf8tm1.1Mrt mutation (1 available); any Fgf8 mutation (18 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
neonatal lethality, complete penetrance ( J:45909 )
• all homozygotes die within a day of birth

nervous system
absent inferior colliculus ( J:45909 )
• inferior collicular (posterior midbrain) tissue is deleted
absent olfactory bulb ( J:45909 )
• olfactory bulbs are absent
absent cerebellum ( J:45909 )
• cerebellar tissue (anterior hindbrain) is absent




Genotype
MGI:2176815
ht2
Allelic
Composition		 Fgf8tm1.1Mrt/Fgf8tm1.2Mrt
Genetic
Background		 involves: 129P2/OlaHsd
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fgf8tm1.1Mrt mutation (1 available); any Fgf8 mutation (18 available)
Fgf8tm1.2Mrt mutation (0 available); any Fgf8 mutation (18 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
mortality/aging
prenatal lethality, incomplete penetrance ( J:45909 )
• at E18.5, only 50% of the expected number of compound heterozygotes are found

growth/size/body
decreased embryo size ( J:45909 )
• embryos are categorized into 3 groups determined by severity of phenotype; embryos are generally smaller than wild-type littermates in the least severely affected group 1
• in group 2, embryos are very small and developmentally delayed compared to littermates but mesoderm-derived structures are present
• group 3 embryos which are the most severely affected group resemble Fgf8tm1.2Mrt homozygotes

embryo
abnormal rostral-caudal axis patterning ( J:45909 )
• many group 2 embryos display a failure of posterior development
decreased embryo size ( J:45909 )
• embryos are categorized into 3 groups determined by severity of phenotype; embryos are generally smaller than wild-type littermates in the least severely affected group 1
• in group 2, embryos are very small and developmentally delayed compared to littermates but mesoderm-derived structures are present
• group 3 embryos which are the most severely affected group resemble Fgf8tm1.2Mrt homozygotes

nervous system
abnormal pituitary gland morphology ( J:178252 )
• mutants exhibit severe abnormalities in the pituitary gland
• at E17.5, 2 of 6 mutants show a substantial reduction of anterior pituitary tissue and absence of the posterior lobe while 4 of 6 mutants show a mild pituitary gland phenotype
small embryonic telencephalon ( J:45909 )
• vesicles are abnormally small in group 1 embryos
abnormal midbrain morphology ( J:45909 )
• defects are usually more severe than in Fgftm1.1 homozygotes
absent inferior colliculus ( J:45909 )
• inferior collicular (posterior midbrain) tissue is deleted in group 1 embryos
abnormal hypothalamus morphology ( J:178252 )
• reduction of arginine vasopressin and oxytocin neurons in the supraoptic, suprachiasmatic, and paraventricular nuclei
absent cerebellum ( J:45909 )
• cerebellar tissue (anterior hindbrain) is absent in group 1 embryos; defects are usually more severe than in Fgftm1.1 homozygotes

cardiovascular system
abnormal heart development ( J:45909 )
• many group 2 embryos display cardiac abnormalities

limbs/digits/tail
syndactyly ( J:45909 )
• fusion of two digits is often observed

craniofacial

endocrine/exocrine glands
abnormal pituitary gland morphology ( J:178252 )
• mutants exhibit severe abnormalities in the pituitary gland
• at E17.5, 2 of 6 mutants show a substantial reduction of anterior pituitary tissue and absence of the posterior lobe while 4 of 6 mutants show a mild pituitary gland phenotype




Genotype
MGI:2677315
ht3
Allelic
Composition		 Fgf8tm1.1Mrt/Fgf8tm1.4Mrt
Genetic
Background		 involves: 129P2/OlaHsd
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fgf8tm1.1Mrt mutation (1 available); any Fgf8 mutation (18 available)
Fgf8tm1.4Mrt mutation (0 available); any Fgf8 mutation (18 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
nervous system
decreased neuron apoptosis ( J:111586 )
• at E10.5 fewer apoptotic cells are detected at the telencephalic midline than in the conditional Fgf8 knockout mice

cellular
decreased neuron apoptosis ( J:111586 )
• at E10.5 fewer apoptotic cells are detected at the telencephalic midline than in the conditional Fgf8 knockout mice




Genotype
MGI:3654832
cn4
Allelic
Composition		 Fgf8tm1.1Mrt/Fgf8tm1.4Mrt
Foxg1tm1M/Foxg1+
Genetic
Background		 involves: 129P2/OlaHsd
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fgf8tm1.1Mrt mutation (1 available); any Fgf8 mutation (18 available)
Fgf8tm1.4Mrt mutation (0 available); any Fgf8 mutation (18 available)
Foxg1tm1M mutation (0 available); any Foxg1 mutation (28 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
nervous system
abnormal neuron apoptosis ( J:111586 )
• at E10.5 in the telencephalic midline, extent of apoptosis in Foxg1 hypomorphs resembles wild-type more than Fgf8tm1.1Mrt/Fgf8tm1.4Mrt hypomorphs

cellular
abnormal neuron apoptosis ( J:111586 )
• at E10.5 in the telencephalic midline, extent of apoptosis in Foxg1 hypomorphs resembles wild-type more than Fgf8tm1.1Mrt/Fgf8tm1.4Mrt hypomorphs




Genotype
MGI:3654834
cn5
Allelic
Composition		 Fgf8tm1.1Mrt/Fgf8tm1.4Mrt
Foxg1tm1(cre)Skm/Foxg1+
Genetic
Background		 involves: 129P2/OlaHsd
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fgf8tm1.1Mrt mutation (1 available); any Fgf8 mutation (18 available)
Fgf8tm1.4Mrt mutation (0 available); any Fgf8 mutation (18 available)
Foxg1tm1(cre)Skm mutation (2 available); any Foxg1 mutation (28 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
nervous system
increased neuron apoptosis ( J:111586 )
• apoptosis in the telencephalon is increased in a qualitatively similar manner to the Fgf8 conditional KOs, but is more severe

cellular
increased neuron apoptosis ( J:111586 )
• apoptosis in the telencephalon is increased in a qualitatively similar manner to the Fgf8 conditional KOs, but is more severe




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Send questions and comments to User Support. 		last database update
05/07/2024
MGI 6.23 		The Jackson Laboratory