Neural control of body-plan axis in regenerating planaria
Fig 4
Model predictions and experimental regenerative outcomes show matching trends for different fragments along the anterior-posterior axis under different cases.
For normal wild-type regeneration, the model predicts polarized gradients of ERK, β-Cat and Notum for each of the 5 cut fragments (A), which are predicted and found to regenerate as 100% 1H in each of the 5 cut fragments (0% 2H heteromorphoses). Partial (i.e. incompletely blocked) RNAi of β-Cat is predicted to show more morphogen gradient polarity disruption, and therefore more 2H regenerates, in fragments progressively closer to the head (B), a prediction that parallels experimental observations (D). In contrast, model perturbations inhibiting β-Cat stability (e.g. via decreased cAMP with bromocriptine treatment) are predicted to show more morphogen polarity disruption (C), and therefore, a higher frequency of 2H regenerates, in fragments cut closer to the tail (E). These modeling prediction trends are corroborated by experiment (D, E). Note that experimentally, the tail piece was only cut on one side and can consequently only regenerate as a 1H, as it only has one blastema.