Thijs de Zeeuw: Hormonal disobedience in plant cell division control

Plant cells are surrounded by rigid walls that prevent cell migration, and therefore formative cell divisions are critical to generate a functional body pattern from a single embryonic cell. Division plane orientation is an important determinant of formative cell divisions and pattern formation. A major unanswered question is how division plane orientation is genetically controlled, and in particular how this relates to cell geometry. Classical models in the 19th century predicted that cell geometry constrains division plane through a simple physical rule, which is approximated as the shortest wall passing through the centre of the cell. Our group has shown that this geometric default rule can explain most of the divisions in the early Arabidopsis embryo in 3D (Yoshida et al., 2014). However, all asymmetric divisions disobeyed this rule.

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Interestingly, in auxin-insensitive Arabidopsis embryos all divisions can be explained by simple geometric default rules, suggesting that transcriptional response to the auxin hormone is required to suppress default divisions. With this knowledge we can try to unravel the regulation of oriented cell division by geometric and genetic cues. In my project, I am using a combined genetic, cell biological, molecular and computational approach to address how auxin dependent gene regulation suppresses default divisions, and what cellular reorganization mediates this activity.

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Palovaara, J. de Zeeuw, T., Annual reviews (2017)

Yoshida et al., Dev. Cell (2014)