354회 Cell cycle controls and plant growth and development

354회

연사 :  왕 명 현, 강원대학교 생명공학부

제목: Cell cycle controls and plant growth and development

Abstract

Plant growth and development is a highly coordinated process between cell proliferation and cell differentiation. The cell cycle in plants is regulated by cyclin dependent kinases (CDKs), which are activated by association with cyclins and can be inhibited by the action of small protein inhibitors. Today, we discuss how the cell-cycle regulators coordinate cell proliferation and differentiation in the transgenic plants. To study the potential cyclin dependent kinase (cdk) regulators in plant, we employed an improved two-hybrid screening system to isolate Arabidopsis genes encoding G1 specific cyclin-interacting proteins (p22^ack1, encoding a novel 22 kDa protein bound to cyclin D1). The p22^ack1 is a potent inhibitor of cyclin D1 kinase and arrests the progression of G1 phase. Arabidopsis p22^ack1 transgenic plant showed growth retardation due to strong inhibition of meristematic cell division in the leaf meristem and the severity of retardation is directly related to the level of p22^ack1. The alteration of leaf shape from oval to dentate was observed in the p22^ack1 Arabidopsis transgenic plants, where as dentate form of tomato leaf was changed to oval by the overexpression of the cyclin D1. The alteration of the leaf shape and the growth arrest shown by p22^ack1 transgenic plants were successfully rescued by the cross-pollination of cyclin D1 overproducing transgenic plants, suggesting that p22^ack1 and cyclin D1 are major factors for early leaf formation and rate-limiting factor for cell cycle progression in the leaf meristem.