Aurora A depletion reveals centrosome-independent polarization mechanism in Caenorhabditis elegans.
How living systems break symmetry in an organized manner is a fundamental question in biology. In wild-type Caenorhabditis elegans zygotes, symmetry breaking during anterior-posterior axis specification is guided by centrosomes, resulting in anterior-directed cortical flows and a single posterior PAR-2 domain. We uncover that C. elegans zygotes depleted of the Aurora A kinase AIR-1 or lacking centrosomes entirely usually establish two posterior PAR-2 domains, one at each pole. We demonstrate that AIR-1 prevents symmetry breaking early in the cell cycle, whereas centrosomal AIR-1 instructs polarity initiation thereafter. Using triangular microfabricated chambers, we establish that bipolarity of air-1(RNAi) embryos occurs effectively in a cell-shape and curvature-dependent manner. Furthermore, we develop an integrated physical description of symmetry breaking, wherein local PAR-2-dependent weakening of the actin cortex, together with mutual inhibition of anterior and posterior PAR proteins, provides a mechanism for spontaneous symmetry breaking without centrosomes.
['Klinkert|Kerstin|K|0000-0001-5268-3710', 'Levernier|Nicolas|N|', 'Gross|Peter|P|', 'Gentili|Christian|C|', 'von Tobel|Lukas|L|', 'Pierron|Marie|M|', 'Busso|Coralie|C|', 'Herrman|Sarah|S|', 'Grill|Stephan W|SW|', 'Kruse|Karsten|K|', 'Gönczy|Pierre|P|0000-0002-6305-6883']
D000818:Animals D064096:Aurora Kinase A D019521:Body Patterning D017173:Caenorhabditis elegans D029742:Caenorhabditis elegans Proteins D018385:Centrosome D015053:Zygote
Aurora A symmetry breaking C. elegans anterior-posterior polarity cell biology physical analysis