雙受精（Double fertilization）是一種在生物學(xué)上具有獨(dú)特意義的生殖系統(tǒng)，被認(rèn)為是開花植物演化中的一個(gè)關(guān)鍵創(chuàng)新,。與動(dòng)物受精不同的是,，雙受精涉及一對(duì)精細(xì)胞通過不同子細(xì)胞的選擇性分裂的生成,。
現(xiàn)在，一種新的F-box蛋白,，名為FBL17,，被發(fā)現(xiàn)在擬南芥中能促進(jìn)雙精細(xì)胞的生成。在雄性生殖細(xì)胞中,，F(xiàn)BL17以KRP7為目標(biāo),，后者是依賴于細(xì)胞周期蛋白的激酶的一個(gè)抑制因子。開花植物所用的這一細(xì)胞周期調(diào)控機(jī)制在酵母和動(dòng)物細(xì)胞之間是在演化上保留下來的,，這項(xiàng)新的研究工作說明了調(diào)控機(jī)制是怎樣演化來適應(yīng)特殊環(huán)境的,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 455, 1134-1137 (23 October 2008) | doi:10.1038/nature07289
Control of plant germline proliferation by SCFFBL17 degradation of cell cycle inhibitors
Hyo Jung Kim1, Sung Aeong Oh3,4, Lynette Brownfield3, Sung Hyun Hong1, Hojin Ryu1, Ildoo Hwang1, David Twell3 & Hong Gil Nam1,2
1 Division of Molecular Life Sciences,
2 School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784, South Korea
3 Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
4 Present address: School of Life Sciences, Kyungpook National University, Daegu 702-701, South Korea.
Flowering plants possess a unique reproductive strategy, involving double fertilization by twin sperm cells1. Unlike animal germ lines, the male germ cell lineage in plants only forms after meiosis and involves asymmetric division of haploid microspores, to produce a large, non-germline vegetative cell and a germ cell that undergoes one further division to produce the twin sperm cells2. Although this switch in cell cycle control is critical for sperm cell production and delivery, the underlying molecular mechanisms are unknown. Here we identify a novel F-box protein ofArabidopsis thaliana, designated FBL17 (F-box-like 17), that enables this switch by targeting the degradation of cyclin-dependent kinase A;1 inhibitors specifically in male germ cells. We show that FBL17 is transiently expressed in the male germ line after asymmetric division and forms an SKP1–Cullin1–F-box protein (SCF) E3 ubiquitin ligase complex (SCFFBL17) that targets the cyclin-dependent kinase inhibitors KRP6 and KRP7 for proteasome-dependent degradation. Accordingly, the loss of FBL17 function leads to the stabilization of KRP6 and inhibition of germ cell cycle progression. Our results identify SCFFBL17 as an essential male germ cell proliferation complex that promotes twin sperm cell production and double fertilization in flowering plants.
