Fig. 7: SPL/NZZ, by indirectly regulating PIN1 expression, determine the MMC differentiation through an auxin-dependent network. | Nature Communications

Fig. 7: SPL/NZZ, by indirectly regulating PIN1 expression, determine the MMC differentiation through an auxin-dependent network.

From: SPOROCYTELESS/NOZZLE cooperates with MADS-domain transcription factors to regulate an auxin-dependent network controlling Megaspore-Mother-Cell differentiation

Fig. 7: SPL/NZZ, by indirectly regulating PIN1 expression, determine the MMC differentiation through an auxin-dependent network.The alternative text for this image may have been generated using AI.

A In the wild type, SPL/NZZ interacts with the ovule-identity MADS-domain complex to inhibit ANT and other chalazal genes expression, facilitating auxin accumulation in the nucellus and subsequently enabling the ARF-mediated auxin response required to promote the MMC differentiation. B In the spl/nzz mutant, ANT and other chalazal genes are expressed in the nucellus, leading to the downregulation of PIN1 and to an auxin subthreshold concentration, which disables the post-translational activation of the ARFs, necessary for MMC formation. C In the ant spl/nzz mutant, the inhibition of PIN1 does not take place, allowing the formation of the MMC even in the absence of SPL/NZZ. D Expressing PIN1 under the control of the SPL/NZZ promoter in the spl/nzz mutant, is sufficient to restore the proper auxin threshold in the nucellus and the ARF-mediated auxin response required for the MMC differentiation. E The expression of the non-degradable shy2.6 isoform in the wild-type nucellus leads to the post-translational deactivation of the ARFs, resulting in the absence of the MMC formation. F Increasing ARF levels in the spl/nzz mutant can overcome the repressive state caused by Aux/IAAs over-accumulation, determining the MMC differentiation.

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