Phenotypes Associated with This Genotype

Genotype
MGI:4949266

• Allelic Composition: Mir9-2^tm1Sia/Mir9-2^tm1Sia; Mir9-3^tm1Sia/Mir9-3^tm1Sia
• Genetic Background: involves: C57BL/6 * CBA

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

mortality/aging

postnatal lethality, complete penetrance ( J:170671 )

• die within 1 week after birth

nervous system

abnormal brain interneuron morphology ( J:170671 )

• barely any interneurons are present in the pallium

• however, interneurons appear to be normally specified in the medial ganglionic eminences and in the rostral migratory stream to the olfactory bulb

abnormal inferior colliculus morphology ( J:170671 )

abnormal globus pallidus morphology ( J:170671 )

• nearly absent

abnormal amygdala morphology ( J:170671 )

• the basolateral amygdala is absent

abnormal telencephalon morphology ( J:170671 )

• in the ventral telencephalon corticofugal axons poorly innervate the internal capsule, thalmocortical axons are nearly lost before reaching the internal capsule, and the majority of fibers abnormally descend into the hypothalamus

• corridor neurons originating in the lateral ganglionic eminences are expanded and dispersed

abnormal telencephalon development ( J:170671 )

• increase in cell proliferation in the cortices at E12.5

• the pallial-subpallial boundary is shifted dorsally

• the glial palisade of the pallial-subpallial boundary is aberrant and less fasciculated

abnormal cortical marginal zone morphology ( J:170671 )

• reduced at E18.5

decreased Cajal-Retzius cell number ( J:170671 )

• greatly reduced numbers in the marginal zone at E12.5 and E13.5

abnormal cortical ventricular zone morphology ( J:170671 )

• marked reduction of the cortical layers and ventricular zone

• decrease in the numbers of early differentiated Tuj1-, Neurod1- or Tbr1-positive neurons in the preplate at E12.5

• increase in cell proliferation at E13.5

• decrease in the number of cells reentering the cell cycle at E16.5 suggesting a depletion of the progenitor pool

abnormal subpallium development ( J:170671 )

• the proliferating zone is hyperplastic and differentiated structures are reduced

• hyperplastic and the cell-dense proliferating field is expanded into the deep differentiating field at E15.5

abnormal subplate morphology ( J:170671 )

• reduced at E18.5

enlarged lateral ventricles ( J:170671 )

abnormal cerebral hemisphere morphology ( J:170671 )

• small cerebral hemispheres

abnormal cerebral cortex morphology ( J:170671 )

• each cortical projection is greatly reduced

• barely any interneurons are present in the pallium

abnormal stratification in cerebral cortex ( J:170671 )

• at E18.5 calretinin-positive layer I, Cux1-positive layer II/III, Satb2-positive layer II-IV, Rorb-positive layer IV, Er81-positive layer V, and calretinin-positive subplate are reduced

• however, the Foxp2- or Tbr1-positive layer VI is almost normal

thin cerebral cortex ( J:170671 )

• marked reduction of the cortical layers and ventricular zone

• hypoplastic at P1

small olfactory bulb ( J:170671 )

abnormal embryonic/fetal subventricular zone morphology ( J:170671 )

• increase in cell proliferation at E13.5

• thinner with fewer BrdU positive cells in S phase at E15.5

• the Islet1-positive lateral ganglionic eminence subventricular zone is expanded while the differentiating area is reduced at E15.5

abnormal lateral ganglionic eminence morphology ( J:170671 )

• the Islet1-positive lateral ganglionic eminence subventricular zone is expanded while the differentiating area is reduced at E15.5

• at E15.5, but not at E12.5, the number of proliferating cells is increased particularly in the deeper area

abnormal axon morphology ( J:170671 )

• axons of commissural neurons labeled by L1 (corpus callosum, anterior commissure, and fornix/hippocampal commissure) are poorly formed

• corticofugal axons are thin in the pallium

growth/size/body

postnatal growth retardation ( J:170671 )

• severe growth retardation