| Abstract Detail
Growth and Vegetative Development Perroud, Pierre-François [1], Quatrano, Ralph S. [1]. Implication of BRICK1 in protonema cell elongation of Physcomitrella patens. Since there is no cell movement or cell migration in plants, the control and coordination of cell elongation and cell division is of critical importance for the development of cell polarity and tissue/organ morphogenesis. Among different cellular components, actin cytoskeleton is regarded as central in this process. The best-described actin nucleation pathway uses two complexes, WAVE/SCARE and Arp2/3. Using the moss Physcomitrella patens as model system, we focused this study on PpBRICK1 (brk1), a member of the WAVE/SCAR complex.
When we deleted BRICK1 in P. patens ad we observed a striking reduction of filamentous tip growth in these lines (Del-brk1). Del-brk1 was viable, completed, although slowly, the morphogenetic transition from filaments into leafy shoots and exhibited proper orientation to polarized light. In order to obtain the BRICK1 cellular localization we inserted YFP-BRK construct into Del-brk1. Such approach allowed us rescue totally the mutant phenotypes and to localize BRICK1 exclusively to the site of polarized growth, at the tip of the apical cell. Additionally, Del-brk1 phenotype was totally complemented using the Arabidopsis Brick1 homologue.
To further understand the function of BRICK1 we tested two known markers of cell tip and cell growth: ARPC4, marker of the Arp2/3 complex and AtRABA5d marker of the cell tip. They both are cell tip localized in WT but both lost their localization in Del-brk1. Interestingly, the deletion of ARPC4 did not miss localize YFP-BRICK1, but still affect cell growth. Hence, ARPC4 for is necessary but not sufficient for cell elongation, and BRICK1 and the SCAR/WAVE complex is the key cellular marker at the cell tip that allows cell elongation.
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1 - Washington University in St Louis, Biology
Keywords:
Pyscomitrella patens
cell growth
WAVE/SCAR complex Brick1
protonema.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P26071
Abstract ID:2593 |
