Phenotypes associated with this allele

• Allele Symbol: Kif20b^magoo
• Allele Name: magoo
• Allele ID: MGI:4888744
• Summary: 4 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Kif20b^magoo/Kif20b^magoo	involves: BALB/c * C57BL/6	MGI:6095619
hm2	Kif20b^magoo/Kif20b^magoo	involves: BALB/c * C57BL/6 * C57BL/6J * FVB/N	MGI:5563766
ht3	Kif20b^33cex/Kif20b^magoo	involves: BALB/c * C3HeB/FeJ * C57BL/6 * FVB/N	MGI:5563767
cx4	Kif20b^magoo/Kif20b^magoo Tg(Mbp-MAPT/lacZ)#aCaw/Tg(Mbp-MAPT/lacZ)#aCaw	involves: BALB/c * C57BL/6 * C57BL/6J * FVB/N	MGI:4889076

Genotype
MGI:6095619

hm1

• Allelic Composition: Kif20b^magoo/Kif20b^magoo
• Genetic Background: involves: BALB/c * C57BL/6

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

mortality/aging

neonatal lethality ( J:242310 )

nervous system

abnormal axon extension ( J:242310 )

• axons retract more and pause less than control axons in cortical neurons grown in culture

disorganized cortical plate ( J:242310 )

• cortical plate appears disorganized at E15.5, with fewer neurons and less than half of them oriented properly with apical dendrites perpendicular to the pial surface

abnormal neurite morphology ( J:242310 )

• neocortical neurons exhibit fewer neurites near the soma at E18.5

• minor neurites of polarized neurons average 29% longer than controls

• both axons and minor neurites of neurons in culture are wider and increased widths correlate with looser microtubule packing

abnormal axon morphology ( J:242310 )

• branching on proximal axons appears increased among neurons at E15.5, with 5/15 neurons having at least 1 detectable branch vs. only 3/22 control neurons with one branch each

• embryonic cortical pyramidal neurons exhibit a defect in axon specification

• axons of cortical neurons are 14% shorter but have nearly twice as many collateral branches as control axons

• both axons and minor neurites of neurons in culture are wider and increased widths correlate with looser microtubule packing

• microtubule bundles have more spaces between them and there is less tubulin in the axons

abnormal dendrite morphology ( J:242310 )

• apical dendrites of neocortical neurons are about 30% shorter and have fewer terminal branches at E18.5

• E18.5 neurons apical dendrites appear thinner, with normal width at the base but tapered more quickly and are thinner than controls

• apical dendrites branch much closer to the cell body, at about 1/3 the normal distance

abnormal pyramidal neuron dendrite morphology ( J:242310 )

• pyramidal neurons have thinner apical dendrites

abnormal neuron physiology ( J:242310 )

• isolated embryonic cortical pyramidal neurons that are dissociated and then cultured, show reduced re-polarization in vitro, with only 23% of neurons polarized after 2 days in culture compared to 50% of controls and 46% being multipolar compared to 29% of controls, indicating disruption of the progression from multipolar to polarized

• marker analysis indicates that the polarization defect is not due to a shift in cell or layer fates

• neurons have longer filopodia (by about 30%) on both axons and minor neurites with increased microtubule invasion

growth/size/body

microcephaly ( J:242310 )

cellular

abnormal microtubule cytoskeleton morphology ( J:242310 )

• cortical neurons exhibit looser microtubule packing in axons and minor neurites and increased microtubule invasion in growth cone filopodia

abnormal axon extension ( J:242310 )

• axons retract more and pause less than control axons in cortical neurons grown in culture

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
microcephaly		DOID:10907		J:242310

Genotype
MGI:5563766

hm2

• Allelic Composition: Kif20b^magoo/Kif20b^magoo
• Genetic Background: involves: BALB/c * C57BL/6 * C57BL/6J * FVB/N

nervous system

increased neuron apoptosis ( J:205043 )

• apoptotic cells are frequently seen in the cerebral cortex at E10.5, E12.5 and E14.5 and to a lesser extent at E16.5

• apoptotic cells are present in the progenitor and neuron layers of the cortex

abnormal neuronal precursor proliferation ( J:205043 )

• increase in the percentage of cytokinetic midbodies of apical cortical progenitors that are misaligned and wider

• however, mitotic indices and S phase appear normal in the cortex

abnormal cortical ventricular zone morphology ( J:205043 )

• decrease in thickness and length at E14.5

• at E16.5 the thickness is slightly increased

decreased forebrain size ( J:205043 )

• smaller and rounder at P0

abnormal cerebral cortex morphology ( J:205043 )

• cortical hemisphere length averages 83% of wild-type controls

• the ventricular zone makes up a larger proportion of the cortical thickness at E14.5 and E16.5 because the other layers are very thin

thin cerebral cortex ( J:205043 )

decreased neuronal precursor cell number ( J:205043 )

• decrease in the number of EOMES+ nuclei per field in the subventricular zone at E14.5 and E16.5

cellular

abnormal mitosis ( J:205043 )

• increase in the percentage of cytokinetic midbodies of apical cortical progenitors that are misaligned and wider

• however, mitotic indices and S phase appear normal in the cortex

increased neuron apoptosis ( J:205043 )

• apoptotic cells are frequently seen in the cerebral cortex at E10.5, E12.5 and E14.5 and to a lesser extent at E16.5

• apoptotic cells are present in the progenitor and neuron layers of the cortex

abnormal neuronal precursor proliferation ( J:205043 )

• increase in the percentage of cytokinetic midbodies of apical cortical progenitors that are misaligned and wider

• however, mitotic indices and S phase appear normal in the cortex

Genotype
MGI:5563767

ht3

• Allelic Composition: Kif20b^33cex/Kif20b^magoo
• Genetic Background: involves: BALB/c * C3HeB/FeJ * C57BL/6 * FVB/N

nervous system

abnormal forebrain morphology ( J:205043 )

• small and misshapen

decreased forebrain size ( J:205043 )

growth/size/body

abnormal head morphology ( J:205043 )

• small and misshapen

microcephaly ( J:205043 )

Genotype
MGI:4889076

cx4

• Allelic Composition: Kif20b^magoo/Kif20b^magoo; Tg(Mbp-MAPT/lacZ)#aCaw/Tg(Mbp-MAPT/lacZ)#aCaw
• Genetic Background: involves: BALB/c * C57BL/6 * C57BL/6J * FVB/N

mortality/aging

postnatal lethality, complete penetrance ( J:168258 )

nervous system

abnormal axon extension ( J:168258 )

• mice exhibit occasional ventral misrouting of thalamocortical axons in the ventral telencephalon compared with wild-type mice

forebrain hypoplasia ( J:168258 )

• slightly small

abnormal telencephalon morphology ( J:168258 )

• mice exhibit occasional ventral misrouting of thalamocortical axons in the ventral telencephalon compared with wild-type mice

enlarged lateral ventricles ( J:168258 )

absent olfactory bulb ( J:168258 )

• in some mice

small olfactory bulb ( J:168258 )

• in some mice

vision/eye

iris coloboma ( J:168258 )

• in 38 of 46 mice

microphthalmia ( J:168258 )

• in 38 of 46 mice

craniofacial

abnormal craniofacial morphology ( J:168258 )

cleft palate ( J:168258 )

• in 10 of 42 mice

short snout ( J:168258 )

limbs/digits/tail

abnormal digit morphology ( J:168258 )

• in 13% of mice

digestive/alimentary system

cleft palate ( J:168258 )

• in 10 of 42 mice

cellular

abnormal axon extension ( J:168258 )

• mice exhibit occasional ventral misrouting of thalamocortical axons in the ventral telencephalon compared with wild-type mice

growth/size/body

cleft palate ( J:168258 )

• in 10 of 42 mice

short snout ( J:168258 )

microcephaly ( J:168258 )

• small head