Figure 3.

MP Polarizes Cells Non-Cell Autonomously

(A and B) Confocal projection showing the mp-B4149 apex expressing pPIN1::PIN1-GFP (magenta) before (A) and 8 days after induction of MP-YPet clones (B) (green); arrowheads indicate initiating organs coinciding with MP expression.

(C) Frequency of peripheral MP clones associated with PIN1 convergence patterns (n = 60 peripheral clones of MP).

(D–M) Time series showing epidermal MP-VENUS clones in mp-T370 and associated changes in PIN1-CFP localization.

(D–H) Overview showing two independent clones. Note the gradual increase in expression of both MP and PIN1 within the clones indicating an increase in local auxin levels compared to neighboring regions (asterisk in G).

(I–M) Magnified view of the dotted rectangle in (D). The asterisk in (I) marks the cell before MP-VENUS induction, corresponding to the future clone.

(N) Longitudinal optical section showing a sub-epidermal polarity response to the epidermal clone.

(O) Cross-section showing lateral PIN1 polarity toward the MP clone in the sub-epidermal layer.

(P) PIN1-CFP convergence in the epidermal cell layer in response to a sub-epidermal MP clone.

(Q) Longitudinal reconstructed section of (P) showing a sub-epidermal MP-VENUS clone.

The arrows indicate the estimated PIN polarity direction within the cells. Scale bars, 30 μm (A and B), 10 μm (D–H and N–Q), 4 μm (I), and 5 μm (J–M). See also Figures S3 and S4 and Movies S2 and S3.