783253.fig.004a
(a)
783253.fig.004b
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783253.fig.004c
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783253.fig.004d
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Figure 4: Gene regulation by sRNA movement. (a) Release of siRNAs from transposons in the vegetative nucleus. Those are transported to the sperm nucleus enforcing transposon silencing there. (b) A similar mechanism leads to siRNAs production in the endosperm and their role in embryo chromatin silencing. (c) Control of adaxial and abaxial identity through ta-siRNA and miRNA gradients. (d) Control of xylem patterning through miRNA gradients [63].