Edinburgh, Scotland, United Kingdom - TAIR
Edinburgh, Scotland, United Kingdom - TAIR
Edinburgh, Scotland, United Kingdom - TAIR
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Leaf size is regulated by a cell-autonomous<br />
system linking cell proliferation and postmitotic<br />
cell enlargement<br />
During leaf development, a defect in cell proliferation often triggers enhanced<br />
post-mitotic cell enlargement. This phenomenon is termed compensation. For<br />
example, a Kip-related protein2 overexpressor (KRP2 o/x) and an angustifolia3<br />
(an3) mutant show atypical compensation. In leaf primordia, differentiating cells<br />
and proliferating cells are found in the apical and basal regions, respectively.<br />
Until now, how, where and when cells in leaf primordia recognize the defect of<br />
cell proliferation remained to be elucidated. In particular, whether compensation<br />
is induced non-cell-autonomously or not is totally unknown. To solve these<br />
questions, we designed an experimental system, which can make mosaic leaves<br />
expressing KRP2 or AN3 by CRE/Lox.<br />
First, we assessed the functionality of our system. When KRP2 overexpression<br />
was shut off within the whole very young leaf primordium, compensation was<br />
restored, suggesting that the system was functional. We next examined whether<br />
KRP2 directly regulates enhanced cell enlargement. When KRP2<br />
overexpression was induced in the postmitotic cells, cell enlargement was not<br />
enhanced, supporting the idea that enhanced cell enlargement was not a direct<br />
function of KRP2 but caused by a defect in cell proliferation. As for cell autonomy,<br />
we analyzed cell size in mosaics. We found that KRP2 mosaics contained two<br />
distinct cell-size classes that were equivalent to wild-type and KRP2 o/x in size,<br />
respectively. This fact indicated that compensation in KRP2 o/x is induced cellautonomously.<br />
Indeed, in the boundary of mosaics, size of genotypically<br />
wild-type and KRP2 o/x cells are not affected by the other genotype. Our results<br />
suggested that the activity of cell proliferation is memorized in each cell at least<br />
in the case of KRP2 o/x. We will discuss the system behind the compensation<br />
based on these results and data from AN3 mosaics now being characterized.<br />
73<br />
C22<br />
Wednesday 17:30 - 17:45<br />
Development<br />
Kensuke Kawade1<br />
Gorou Horiguchi2<br />
Hirokazu Tsukaya1,3<br />
1Graduate School of<br />
Science<br />
The University of Tokyo<br />
Tokyo<br />
Japan<br />
2 College of Science<br />
Rikkyo University<br />
Tokyo<br />
Japan<br />
3 National Institute for<br />
Basic Biology<br />
Okazaki<br />
Aichi<br />
Japan
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