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#VPCs

2 public questions tagged with this topic.

C-Elegans Development-l

Which of the following proteins is essential for specifying VPCs in C. elegans?

LIN-39 is Sex Combs Reduced-like Hox protein expressed in central body region P3.p-P8.p controlling vulval precursor competence and central patterning. LIN-39 maintains LET-23 EGFR expression, prevents premature fusion of VPCs with hyp7 syncytium during L1-L2 via repression of eff-1 fusogen. Without LIN-39, all six VPCs fuse and become refractory to LIN-3 induction, causing vulvaless phenotype despite normal anchor cell signaling and positioning. LIN-39 cooperates with Wnt effectors BAR-1 beta-catenin, LIN-31 forkhead, and other Hox genes, linking anteroposterior patterning to tissue competence.

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 8: LIN-39 Hox gene and vulval precursor cell competence.

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Elegans -ll

Which protein prevents LIN-3 activation in tertiary VPCs?

Lateral inhibition ensures tertiary fate protection. After induction, P6.p primary cell expresses LAG-2 ligands activating LIN-12 Notch in P5.p and P7.p, specifying secondary fate. Secondary cells also secrete DSL signals that activate LIN-12 in more distant P3.p, P4.p, P8.p. LIN-12 activation induces transcriptional repressors that prevent activation of LET-23 EGFR pathway by low LIN-3 and promotes hyp7 fusion via inhibition of egl-17 and vulval genes. Thus LIN-12 prevents LIN-3 activation from specifying vulval fate in tertiary cells, ensuring correct 3-2-1-2-3 pattern by restricting EGFR responsiveness through Notch-mediated lateral inhibition mechanism.

Ref: Sternberg WormBook Vulval Development: LIN-12 prevents LIN-3 activation in tertiary VPCs via lateral inhibition.

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