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#ABp fate

2 public questions tagged with this topic.

Elegans -ll

Which factor ensures ABp fate specification?

ABp fate distinguishing dorsal versus ventral AB lineage derivatives depends on GLP-1 Notch receptor activation. GLP-1 protein segregates to all AB daughters but functionally active only in ABp due to contact with P2 ligands APX-1 and LAG-2. Activated GLP-1 ICD upregulates Notch target genes ref-1 family, promoting ABp-specific blastomere divisions generating dorsal epidermis and distinct pharyngeal cells. In glp-1 mutants ABp transforms to ABa, equalizing lineage. Therefore GLP-1 presence and selective activation is decisive intrinsic factor ensuring ABp identity, integrating positional signal from P2 to create anterior-posterior and dorsal-ventral pattern within early embryo ectoderm contribution.

Ref: Mango et al. 1994; Gilbert Chapter 4: GLP-1 Notch receptor ensures ABp fate specification in C. elegans.

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Elegans -ll

Which signaling molecule from P2 influences ABp fate?

At 4-cell stage, dorsal ABp and ventral EMS-P2 contacts establish ABa versus ABp asymmetry. P2 presents Delta-like ligands APX-1 and LAG-2, which bind GLP-1 Notch receptor highly expressed on ABp membrane, owing to par-3 mediated receptor localization. GLP-1 activation cleaves intracellular domain, activating Notch targets in ABp and repressing ABa-specific genes. Thus GLP-1 functions as instructive receptor transducing P2 positional information. Ablation of P2 or glp-1 mutants cause ABp to adopt ABa fate, producing symmetrical pharynx pattern, confirming Notch-mediated signaling from P2 determines dorsal-ventral distinction of AB lineage.

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 4: GLP-1 Notch signaling from P2 influences ABp fate.

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