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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID
Hoxa1tm1Ipc
targeted mutation 1, Pierre Chambon
MGI:1857504
Summary 3 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
Hoxa1tm1Ipc/Hoxa1tm1Ipc involves: 129S2/SvPas MGI:3773347
hm2
Hoxa1tm1Ipc/Hoxa1tm1Ipc involves: 129S2/SvPas * C57BL/6 MGI:2175066
cx3
Hoxa1tm1Ipc/Hoxa1tm1Ipc
Hoxb1tm1Ipc/Hoxb1tm1Ipc
involves: 129S2/SvPas * 129S7/SvEvBrd MGI:3773282


Genotype
MGI:3773347
hm1
Allelic
Composition
Hoxa1tm1Ipc/Hoxa1tm1Ipc
Genetic
Background
involves: 129S2/SvPas
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxa1tm1Ipc mutation (0 available); any Hoxa1 mutation (14 available)
phenotype observed in females
phenotype observed in males
N normal phenotype



Genotype
MGI:2175066
hm2
Allelic
Composition
Hoxa1tm1Ipc/Hoxa1tm1Ipc
Genetic
Background
involves: 129S2/SvPas * C57BL/6
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxa1tm1Ipc mutation (0 available); any Hoxa1 mutation (14 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• homozygous mutant embryos die at birth from anoxia

homeostasis/metabolism
• homozygotes fail to turn pink within 15 min after Cesarean section
• homozygotes die from anoxia

respiratory system
• homozygotes fail to commence breathing; their lungs never inflate prior to death
• homozygotes lack the roots of the glossopharyngeal (IX) and vagus (X) nerves and are therefore unable to transmit respiratory stimuli to the hindbrain

muscle
• at 15-45 min after Cesarean delivery, homozygotes show spasmodic muscular contractions, with arching of the back and neck

nervous system
• at E9.5, 3 of 6 homozygotes exhibit a variable delay in neural tube closure at the hinbrain level (r2 to r8)
• however, closure eventually occurs such that no significant differences in this region hindbrain are observed at E10.5 or later
• at E15.5 and E17.5, homozygotes show multiple defects in the region corresponding to the level of r4 to r7
• at E15.5 and E17.5, homozygotes show variable malformations of that part of the rhombencephalon derived from r4 to r7
• at E15.5 and E17.5, the motor nucleus of the facial nerve (derived from r4 and r5) is absent
• at E15.5, homozygotes lack cochlear ganglion cells (J:71547)
• 30% of 5RA-treated homozygotes display rescued cochlear ganglion cells (J:71547)
• at E15.5, the superior ganglion (jugular) of the vagus (X) nerve is malformed or absent
• in contrast, the inferior ganglion (nodose) of the vagus (X) nerve is apparently normal
• at E15.5 and E17.5, the nuclei of cranial nerves VI and VIII-XI are most likely absent, as is the nucleus of cranial nerve VII
• notably, the hypoglossal (XII) nerve nucleus, partly originating in r8) is normal
• at E15.5 and E17.5, the mutant facial nerve and nerve root are absent
• at E15.5 and E17.5, the root of the glossopharyngeal (IX) nerve is absent
• at E15.5 and E17.5, the root of the vagus (X) nerve is absent
• at E15.5 and E17.5, the root of the acoustic (VIII) nerve is absent

hearing/vestibular/ear
• at E12.0, homozygotes display small otocysts displaced laterally from the neural tube
• 35% of 5RA-treated homozygotes exhibit improved otocyst morphology
• at E15.5 and E17.5, homozygotes display variable inner ear abnormalities (J:23837)
• at E18.5, homozygotes show subtle symmetrical alterations of the bones surrounding the inner ear (J:23837)
• a single maternal administration of a sub-teratogenic dose (5 mg/kg) of retinoic acid (5RA) between E8.0 + 2 hrs (otic placode stage, 5RA-8) and E8.75 (early otic cup stage, 5RA-8.85) rescues both vestibular and cochlear structural defects in mutant mice (J:71547)
• at E18.5, the mutant cochlea is either absent (48%) or present as a poorly developed, inflated cystic capsule (52%)
• at E15.5, the cochlear neurosensory region is absent
• at E18.5, the mutant cochlea is absent (J:23837)
• 31% of 5RA-8-treated homozygotes display rescue of cochlear structures; the extent of rescue is often asymmetrical between the two ears (J:71547)
• only 25% of cochleae are absent in 5RA-8- or 5RA-8.75-treated mutant mice relative to 48% in untreated mutant mice (J:71547)
• at E16.0, 62% of homozygotes show absence of the common crus
• at E16.0, 62% of homozygotes show absence of the posterior semicircular canal
• at E15.5, the number and spatial distribution of the cristae is variable, depending on the extent of vestibular defects
• in 5RA-8-treated homozygotes, the degree of rescue of semicircular canals, utricle, and saccule correlate with the recovery of normal numebr/distribution of cristae and macule
• at E16.0, 62% of homozygotes show absence of the anterior semicircular canal
• in contrast, the lateral semicircular canal is present
• at E18.5, vestibular structures are either severely underdeveloped or highly dysmorphic
• 5RA-8-treated homozygotes display rescue of vestibular structures
• at E15.5 and E17.5, homozygotes exhibit a dilated membranous labyrinth of rudimentary morphology (J:23837)
• at E16.0, 62% of homozygotes show a severely abnormal membranous labyrinth; the remaining 38% show a less severe but highly dysmorphic phenotype with identifiable semicircular canals of abnormal planes lumen and size and inner ear structures that resemble an inflated sac (J:71547)
• 27% of 5RA-8.25-8.75-treated homozygotes exhibit a morphologically improved membranous labyrinth, with a similar degree of rescue to that of the cartilaginous capsules: the endolyphatic duct, semicircular canals, utricle, saccule, cochlear duct are present while recovery of cochlear turning is evident in all but one (J:71547)
• in 5RA-8-treated homozygotes, the degree of rescue of semicircular canals, utricle, and saccule correlate with the recovery of normal numebr/distribution of cristae and macule (J:71547)
• at E15.5, the number and spatial distribution of the maculae is variable, depending on the extent of vestibular defects
• in 5RA-8-treated homozygotes, the degree of rescue of semicircular canals, utricle, and saccule correlate with the recovery of normal numebr/distribution of cristae and macule
• at E16.0, 62% of homozygotes show absence of the utricle
• at E15.5, the number and spatial distribution of the maculae is variable, depending on the extent of vestibular defects
• in 5RA-8-treated homozygotes, the degree of rescue of semicircular canals, utricle, and saccule correlate with the recovery of normal numebr/distribution of cristae and macule
• at E16.0, 62% of homozygotes show absence of the saccule
• at E16.0, 62% of homozygotes show absence of the endolymphatic duct
• at E16.0, 62% of homozygotes show absence of the endolymphatic sac
• at E15.5 and E17.5, the mutant periotic capsule is incomplete ventromedially; as a result, the membranous labyrinth protrudes into adjacent soft tissues
• at E18.5, the mutant tympanic ring is of normal size but abnormal position

craniofacial
• at E18.5, the mutant basioccipital bone lacks a concave lateral border (J:23837)
• at E18.5, the anterior edge of the basioccipital is abnormal; this defect is often not rescued by RA treatment (J:71547)
• at E18.5, the mutant interparietal bone exhibits a more acute outline at its lateral extremities
• at E18.5, mutant exoccipital bones are compressed along the rostrocaudal axis

skeleton
• at E18.5, the mutant basioccipital bone lacks a concave lateral border (J:23837)
• at E18.5, the anterior edge of the basioccipital is abnormal; this defect is often not rescued by RA treatment (J:71547)
• at E18.5, the mutant interparietal bone exhibits a more acute outline at its lateral extremities
• at E18.5, mutant exoccipital bones are compressed along the rostrocaudal axis

embryo
• at E9.5, 3 of 6 homozygotes exhibit a variable delay in neural tube closure at the hinbrain level (r2 to r8)
• however, closure eventually occurs such that no significant differences in this region hindbrain are observed at E10.5 or later
• at E15.5 and E17.5, homozygotes show multiple defects in the region corresponding to the level of r4 to r7




Genotype
MGI:3773282
cx3
Allelic
Composition
Hoxa1tm1Ipc/Hoxa1tm1Ipc
Hoxb1tm1Ipc/Hoxb1tm1Ipc
Genetic
Background
involves: 129S2/SvPas * 129S7/SvEvBrd
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hoxa1tm1Ipc mutation (0 available); any Hoxa1 mutation (14 available)
Hoxb1tm1Ipc mutation (0 available); any Hoxb1 mutation (24 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
embryo
N
• patterning of the second pharyngeal arch is normal despite the failure of neural crest cells to migrate into the arch
• neural crest cells emanating from r4 fail to migrate properly and populate the second pharyngeal arch
• however, neural crest cell differentiation, proliferation and apoptosis are normal
• neural crest cells fail to delaminate from r4

muscle
N
• mice exhibit normal cranial myogenesis

cellular
• neural crest cells emanating from r4 fail to migrate properly and populate the second pharyngeal arch
• however, neural crest cell differentiation, proliferation and apoptosis are normal
• neural crest cells fail to delaminate from r4





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last database update
12/10/2024
MGI 6.24
The Jackson Laboratory