Mouse Genome Informatics
hm1
    Egr2tm1Jmi/Egr2tm1Jmi
Not Specified
Key:
phenotype observed in females WTSI Wellcome Trust Sanger Institute
phenotype observed in males EuPh Europhenome
N normal phenotype

Runted phenotype and hindbrain defect of Egr2tm1Jmi/Egr2tm1Jmi mice

mortality/aging
• 40% die within the first week of life, the remaining homozygotes survive into the third week of life

behavior/neurological
• severe tremors are seen

growth/size

nervous system
• increased numbers of proliferating Schwann cells are seen at P14
• at E10.5, in 14% of mutants both rhombomeres 3 and 5 are absent, in 57% fusion of cranial nerves V, VII, and VIII is seen, and in 29% fusion of cranial nerves IX and X is seen
• an abundance of undifferentiated Schwann cells are seen associated with individual axons of the sciatic nerve (J:96641)
• at postnatal day 14 increased proliferation of Schwann cells is seen with 11.3 +/- 1.9% of the nuclei BrdU+ compared to less than 0.9% in wild-type mice (J:99824)
• at P14 the sciatic nerve is thin and translucent
• the number of large and medium claiber axons is normal but, most lack myelin
• myelination is absent; however, no signs of demyelination are seen (J:96641)

cellular
• increased numbers of proliferating Schwann cells are seen at P14