Introduction to vulval induction in C. elegans

C. elegans are hermaphrodites and change from male to female as they mature. The vulval induction in C. elegans occurs in the larval stage from six cells called the vulval precursor cells (VPCs).

Paracrine and Juxtacrine Signaling

• The cell connecting the gonad to the VPCs is called the anchor cell.
• The anchor cell secretes LIN-3 protein, a paracrine factor, that activates the RTK pathway.
• The absence of the anchor cell or mutation in the lin-3 gene results in the VPCs becoming part of the hypodermis.
• LIN-3 forms a concentration gradient, with the closest VPC receiving the highest concentration and forming the central vulval cells.

Notch-Delta and Lateral Inhibition

• The formation of the anchor cell is mediated by the Notch gene homologue, lin-12.
• Two adjacent cells, Z1.ppp and Z4.aaa, have the potential to become the anchor cell.
• The decision is made by chance, with the cell secreting more LAG-2 becoming the anchor cell and the other becoming the uterine precursor.
• The LIN-12 protein is used again during vulva formation to stop the lateral vulval cells from forming the central vulval phenotype.

Conclusion

• The process of vulval induction in C. elegans involves paracrine and juxtacrine signaling, as well as Notch-Delta and lateral inhibition mechanisms.
• These mechanisms determine the fate of the vulval precursor cells, forming the vulva or contributing to the hypodermis.