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#hindlimb

2 public questions tagged with this topic.

Limb Development -l

Which signaling molecule is required for initiating hindlimb development?

Hindlimb initiation and distal patterning integrate Tbx4-Pitx1 selector program with posterior Hox inputs. While Tbx4 and Pitx1 are primary determinants imposing leg identity, posterior distal Hox genes such as Hoxd13 reinforce hindlimb autopod expansion, digit morphogenesis, and maintenance of hindlimb-specific enhancers downstream of Pitx1. Pitx1 activates Tbx4 and represses forelimb program, FGF10 initiates outgrowth, Tbx5 marks forelimb. Among provided choices, Hoxd13 represents distal hindlimb patterning component linked to hindlimb stylization, consistent with its posterior-restricted function in leg morphogenesis and digit development.

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 19: Hindlimb development – Pitx1, Tbx4 and distal Hox13 patterning.

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Limb Development -l

Which factor stabilizes hindlimb formation in the lateral plate mesoderm?

Hindlimb field stabilization within posterior lateral plate mesoderm depends on caudalizing Wnt signaling that fortifies hindlimb program. Wnt8c expressed in tailbud and posterior lateral plate activates canonical beta-catenin pathway, stabilizing FGF10 transcription in presumptive hindlimb mesenchyme and permitting subsequent activation of Tbx4, Pitx1, and hindlimb enhancers. Forelimb equivalent is Wnt3a-Wnt2b upstream of Tbx5, beta-catenin serves as common intracellular transducer in both, retinoic acid provides permissive flank environment. Localized Wnt8c thus designates lumbosacral competence zone positioning hindlimbs correctly and ensuring outgrowth.

Ref: NCBI Bookshelf, Developmental Biology: Wnt8c beta-catenin stabilization of hindlimb field and Tbx4 activation.

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