A small, novel protein highly conserved in plants and animals promotes the polarized growth and division of maize leaf epidermal cells

作者：Frank MJ; Smith LG^*

来源：Current Biology, 2002, 12(10): 849-853.

DOI：10.1016/S0960-9822(02)00819-9

Plant cell shapes are defined by their surrounding walls, but microtubules and F-actin both play critical roles in cell morphogenesis by guiding the deposition of wall materials in expanding cells [1-7]. Leaf epidermal cells have lobed shapes, which are thought to arise through a microtubule-dependent pattern of locally polarized growth [8-13]. We have isolated a recessive mutation, brk1, which blocks the formation of epidermal cell lobes in the maize leaf. Mutant epidermal cells expand to the same extent as wild-type cells but fail to establish polar growth sites from which lobes arise. In expanding brk1 epidermal cells, microtubule organization differs little from that in wild-type, but localized enrichments of cortical F-actin seen at the tips of emerging lobes in wild-type cells fail to form. These observations suggest a critical role for F-actin in lobe formation and together with additional effects of brk1 on the morphogenesis of stomata and hairs suggest that Brk1 promotes multiple, actin-dependent cell polarization events in the developing leaf epidermis. The Brk1 gene encodes a novel, 8 kD protein that is highly conserved in plants and animals, suggesting that BRK1-related proteins may function in actin-dependent aspects of cell polarization in a wide spectrum of eukaryotic organisms.

• 出版日期2002-5-14