Phenotypes Associated with This Genotype

Genotype
MGI:3700768

• Allelic Composition: Amn^amn/Amn^amn
• Genetic Background: involves: C57BL/6J

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

mortality/aging

embryonic lethality during organogenesis, complete penetrance ( J:34163 )

• die between E9.5 and E10.5

embryo

increased embryonic tissue cell apoptosis ( J:50810 )

• embryos exhibit an increase in overall level of cell death, with high levels in the distal anterior region

abnormal ectoderm development ( J:51542 , J:34163 )

• development of the embryonic ectoderm appears delayed by at least 1.5 days (J:51542)

• embryonic ectoderm is small, underdeveloped, remains undifferentiated and generates no amnion (J:34163)

abnormal mesoderm development ( J:34163 )

• the mesoderm does not become organized into the node, notochord, and somites by E8.5

embryonic growth arrest ( J:34163 )

• homozygotes become developmentally arrested between the mid and late streak stages of gastrulation

abnormal embryonic tissue morphology ( J:50810 )

• at E7-7.5, embryos have a small embryonic region

absent mesoderm ( J:51542 )

• E8.5 embryos do not express the embryonic mesoderm markers Twist1 and Meox1 (Mox1), indicating that paraxial and lateral mesoderm are either not generated or that their generation is delayed

absent notochord ( J:34163 )

• no evidence of notochord production at E8.5

abnormal primitive streak morphology ( J:50810 )

• at E7-7.5 embryos have a short primitive streak

absent primitive node ( J:51542 , J:34163 )

• a definitive node is absent at E8.5 (J:51542)

• although the streak appears to extend to the distal tip of the egg cylinder, no recognizable node is detectable at the late streak stage (E7.5-7.75) or at E8.5 (J:34163)

abnormal primitive streak formation ( J:51542 )

• the middle region of the primitive streak is not appropriately assembled and appears absent

• however, the proximal and distal regions of the streak are properly organized and specified

absent somites ( J:34163 )

• no evidence of somite production

absent amnion ( J:51542 , J:34163 )

• Background Sensitivity: amnion is absent on the C57BL/6 background, although the amniotic cavity forms by the epithelial embryonic ectoderm closing off on itself (J:51542)

• although some mutants appear to form amniotic folds, no amnion is formed (J:34163)

• differentiation of other extraembryonic structures like the chorion, yolk sac blood islands and allantois occurs normally (J:34163)

nervous system

abnormal nervous system development ( J:34163 )

• show no evidence of neural induction

cellular

increased embryonic tissue cell apoptosis ( J:50810 )

• embryos exhibit an increase in overall level of cell death, with high levels in the distal anterior region