All Phenotypes Msgn1<tm1Wb> MGI Mouse

embryonic lethality during organogenesis, complete penetrance ( J:66514 )

• homozygotes die at midgestation following E10.5; survival drops significantly thereafter

increased tail bud apoptosis ( J:66514 )

• increased apoptosis in noted in the mutant tail bud at E9.5

abnormal presomitic mesoderm morphology ( J:66514 )

• at E8.5 (but not prior to E8.0), homozygotes show an expanded presomitic paraxial mesoderm relative to wild-type embryos

absent paraxial mesoderm ( J:66514 )

• by E9.5 dpc, homozygotes completely lack a detectable paraxial mesoderm

• however, notochord and intermediate and lateral mesoderm remain grossly unaffected

incomplete caudal neuropore closure ( J:66514 )

• the neural tube fails to close at the hindlimb level

• normal closure is detected at the rostral region

kinked neural tube ( J:66514 )

• at E9.0, homozygotes display a kinked neural tube posterior to forelimb buds

• in contrast, the head and anterior body structures (e.g. heart) remain unaffected

decreased somite size ( J:66514 )

• after E9.0, somite size is reduced in somites ~8-11

• in contrast, the anterior-most somites (1-7) appear normal

incomplete somite formation ( J:66514 )

• after E9.0, homozygotes show no identifiable somites or segment patterning in the trunk posterior to the forelimbs

• at E10.5, homozygotes lack detectable segmented somites in the interlimb region

• no somites are detectable beyond somite 11

enlarged tail bud ( J:66514 )

• at E9.0, homozygotes display an enlarged tail bud with ectopic blood pools

abnormal fetal growth/weight/body size ( J:66514 )

• at E14.5, the few surviving homozygotes lack a tail and possess a grossly normal but very thin body with relatively normal forelimbs and hindlimbs

enlarged tail bud ( J:66514 )

• at E9.0, homozygotes display an enlarged tail bud with ectopic blood pools

absent tail ( J:66514 )

• at E14.5, homozygotes lack a tail but possess grossly normal limbs

abnormal myotome development ( J:66514 )

• after E9.0, homozygotes display impaired myotomal patterning in somites ~8-11

• at E11.5, myotomes are absent at the interlimb region

• at E12.5, skeletal muscle is absent from the mutant hindlimbs while forelimb muscles are present, albeit reduced in size

absent ribs ( J:66514 )

• at E14.5 and E17.5 dpc, all ribs are absent

abnormal cervical vertebrae morphology ( J:66514 )

• at E14.5 and E17.5, some of the most posterior cervical vertebrae are often malformed and fused

cervical vertebral fusion ( J:66514 )

absent vertebrae ( J:66514 )

• at E14.5 and E17.5, all vertebrae posterior to cervical level are absent

• in contrast, the head skeleton, most cervical vertebrae, and limb skeleton appear largely normal