Analysis Tools
limbs/digits/tail
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• homozygous mice show two penetrant phenotypes: mice show complete loss of proximal and medial phalanges in all digits of hindlimb and forelimb, and fusion of the small sesamoid bones that articulate with the missing elements
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brachydactyly
(
J:59288
)
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• homozygotes have short digits
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• in homozygous forelimbs, each pair of metacarpophalangeal sesamoids is fused at the distal ends, resulting in a forked configuration
• the P2-P3 sesamoids are absent or reduced in overall size
• a novel joint is generated between P3, the fused sesamoids and the metacarpal or metatarsal
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• homozygotes lack all endochondral-derived phalanges (P1 and P2)
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• at 13.5-14 dpc, metacarpals fail to segment in hindlimbs and forelimbs
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• metatarsal are ~90% the length of wild-type: this is not fully penetrant
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• mutants have fused V-shaped metacarpophalangeal sesamoids
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skeleton
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• in homozygous forelimbs, each pair of metacarpophalangeal sesamoids is fused at the distal ends, resulting in a forked configuration
• the P2-P3 sesamoids are absent or reduced in overall size
• a novel joint is generated between P3, the fused sesamoids and the metacarpal or metatarsal
|
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• homozygotes lack all endochondral-derived phalanges (P1 and P2)
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• at 13.5-14 dpc, metacarpals fail to segment in hindlimbs and forelimbs
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• metatarsal are ~90% the length of wild-type: this is not fully penetrant
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• mutants have fused V-shaped metacarpophalangeal sesamoids
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• digit cartilage does not develop in mutants
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cellular
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• at 13.5-14.5 dpc, limbs show a 5-fold increase in cell death compared to wild-type
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• number of proliferating mesenchymal cells at 13.5 dpc in phalangeal region is reduced 6.4-fold in the distal region of the limbs
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