Phenotypes associated with this allele

• Allele Symbol: Tg(Hoxb1-cre)r4Mist
• Allele Name: transgene insertion r4, Michele Studer
• Allele ID: MGI:5006714
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
cn1	Hoxb1^tm1Mist/Hoxb1^tm1Mist Tg(Hoxb1-cre)r4Mist/0 Gt(ROSA)26Sor^tm1(EYFP)Cos/Gt(ROSA)26Sor^+	involves: 129S2/SvPas * 129X1/SvJ * C57BL/6 * CD-1	MGI:5491185
cn2	Hoxb1^tm1.1Mist/Hoxb1^tm1.1Mist Tg(Hoxb1-cre)r4Mist/0 Gt(ROSA)26Sor^tm1(EYFP)Cos/Gt(ROSA)26Sor^+	involves: 129S2/SvPas * 129X1/SvJ * C57BL/6 * CD-1	MGI:5491188

Genotype
MGI:5491185

cn1

• Allelic Composition: Hoxb1^tm1Mist/Hoxb1^tm1Mist; Tg(Hoxb1-cre)r4Mist/0; Gt(ROSA)26Sor^tm1(EYFP)Cos/Gt(ROSA)26Sor⁺
• Genetic Background: involves: 129S2/SvPas * 129X1/SvJ * C57BL/6 * CD-1

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

hearing/vestibular/ear

abnormal organ of Corti morphology ( J:197162 )

• very few crossing medial olivocochlear (MOC) terminals are observed contacting outer hair cells in adult mice

abnormal cochlear outer hair cell morphology ( J:197162 )

• at P8, no difference in shape or organization of outer hair cells (OHCs) is observed at the apical and basal turns relative to wild-type

• morphological defects of OHCs in adults are less severe than observed in constitutive Hoxb1-deficient (Hoxb1^tm1.2Fmr) mice but statistically significant loss of OHCs and moderate OHC ciliar malformations are observed

• no abnormalities are observed in basal regions

increased or absent threshold for auditory brainstem response ( J:197162 )

• at 3 months, threshold is pathologically elevated compared to the normal 40dB, but not as significantly as in Hoxb1^tm1.2Fmr (null) mice

• thresholds are elevated at all ages tested (from 1-12 months), increasing progressively to double the control level

increased susceptibility to age-related hearing loss ( J:197162 )

nervous system

abnormal cochlear outer hair cell morphology ( J:197162 )

• at P8, no difference in shape or organization of outer hair cells (OHCs) is observed at the apical and basal turns relative to wild-type

• morphological defects of OHCs in adults are less severe than observed in constitutive Hoxb1-deficient (Hoxb1^tm1.2Fmr) mice but statistically significant loss of OHCs and moderate OHC ciliar malformations are observed

• no abnormalities are observed in basal regions

abnormal brainstem morphology ( J:197162 )

• area of the ventral nucleus of the lateral lemniscus is reduced by about 50% compared to wild-type controls at P8

abnormal pons morphology ( J:197162 )

• specification and innervation of olivocochlear neurons is abnormal, no crossing olivocochlear (MOC) efferent neurons cross the midline at P8

• the cholinergic population of lateral olivocochlear (LOC) neurons is absent indicating defective specification

abnormal cochlear VIII nucleus morphology ( J:197162 )

• axon pathfinding defects are observed, with ectopic r4-derived projections crossing the midline and innervating the medial nucleus of the trapezoid body (MNTB)

Genotype
MGI:5491188

cn2

• Allelic Composition: Hoxb1^tm1.1Mist/Hoxb1^tm1.1Mist; Tg(Hoxb1-cre)r4Mist/0; Gt(ROSA)26Sor^tm1(EYFP)Cos/Gt(ROSA)26Sor⁺
• Genetic Background: involves: 129S2/SvPas * 129X1/SvJ * C57BL/6 * CD-1

hearing/vestibular/ear

abnormal organ of Corti morphology ( J:197162 )

• very few crossing medial olivocochlear (MOC) terminals are observed contacting outer hair cells in adult mice

abnormal cochlear outer hair cell morphology ( J:197162 )

• at P8, no difference in shape or organization of outer hair cells (OHCs) is observed at the apical and basal turns relative to wild-type, but in adults (3 months), OHC rows are severely disorganized with loss of some hair cells in the apical turn of the cochlea; no inner hair cells (IHCs) are lost

• OHCs in the basal turns show only slight abnormalities in ciliar organization and orientation

increased or absent threshold for auditory brainstem response ( J:197162 )

• at 3 months, threshold is elevated to 90 dB compared to the normal 40dB

• thresholds are elevated at all ages tested (from 1-12 months), increasing progressively to double the control level

abnormal susceptibility to hearing loss ( J:197162 )

• mice raised in acoustic isolation display ABR threshold increases compared to controls, indicating that sensitivity to environmental sounds is not a significant factor

increased susceptibility to age-related hearing loss ( J:197162 )

nervous system

abnormal cochlear outer hair cell morphology ( J:197162 )

• at P8, no difference in shape or organization of outer hair cells (OHCs) is observed at the apical and basal turns relative to wild-type, but in adults (3 months), OHC rows are severely disorganized with loss of some hair cells in the apical turn of the cochlea; no inner hair cells (IHCs) are lost

• OHCs in the basal turns show only slight abnormalities in ciliar organization and orientation

abnormal brainstem morphology ( J:197162 )

• area of the ventral nucleus of the lateral lemniscus is severely reduced by about 90% compared to wild-type controls at P8

abnormal pons morphology ( J:197162 )

• specification and innervation of olivocochlear neurons is abnormal, no medial olivocochlear (MOC) efferent neurons cross the midline at P8

• the cholinergic population of lateral olivocochlear (LOC) neurons is very small indicating defective specification

abnormal cochlear VIII nucleus morphology ( J:197162 )

• axon pathfinding defects are observed, with ectopic r4-derived projections crossing the midline and innervating the medial nucleus of the trapezoid body (MNTB)