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#lens differentiation

2 public questions tagged with this topic.

Eye Lens Induction -l

Which signaling molecule is required for lens differentiation and activates Sox2?

BMP4 expressed in optic vesicle and periocular mesenchyme plays biphasic roles in lens specification. Early BMP4 activates Smad-dependent transcription of Sox2 in head ectoderm that already expresses Pax6, allowing formation of Pax6-Sox2 complex on delta-crystallin enhancer. This triggers lens placode thickening and invagination. Later BMP activity must be attenuated by Noggin in neural retina to permit differentiation. Conditional deletion of Bmpr1a in mouse surface ectoderm abolishes Sox2 upregulation and lens vesicle formation, while exogenous BMP beads rescue competence, confirming require

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 7: BMP signaling in lens induction and Sox2 activation.

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Eye Lens Induction -ll

Which signaling molecule is required for lens differentiation and activates Sox2?

Lens differentiation requires bone morphogenetic protein signaling, particularly BMP4 from optic vesicle, which cooperates with FGF signaling to activate Sox2 and downstream L-Maf in lens placode. BMP4 stimulates Smad1-5-8 phosphorylation promoting Sox2 expression initiating cell cycle exit and crystallin synthesis, while BMP inhibition prevents lens formation. Sonic hedgehog suppresses Pax6 centrally, Wnt3a posteriorizes, Hedgehog generic not lens inductive. Competent head ectoderm receiving BMP4 initiates placodal thickening, demonstrating BMP as differentiation cue linking induction to Sox2

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 12: BMP4 Sox2 activation and lens differentiation cascade.

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