Zhao Da-Zhong, Wang Guan-Fang, Speal Brooke, Ma Hong
Department of Biology and the Life Sciences Consortium, Pennsylvania State University, Pennsylvania 16802, USA.
Genes Dev. 2002 Aug 1;16(15):2021-31. doi: 10.1101/gad.997902.
Cell differentiation is essential for the development of multicellular organisms. In flowering plants, the haploid male gametophytes (pollen grains) are generated in the anther from reproductive cells called microsporocytes. Several types of somatic cells ensure successful pollen development, and thus reproduction. However, it is not clear what genes regulate the differentiation of these diverse, highly specialized cells in the anther. We report here the isolation and characterization of a novel Arabidopsis thaliana male sterile mutant, excess microsporocytes1 (ems1), that produces excess microsporocytes, lacks tapetal cells, and abnormally maintains middle layer cells. Although the meiotic nuclear division in the ems1 mutant is normal, the microsporocytes do not undergo cytokinesis, resulting in failed microsporogenesis and male sterility. The EMS1 gene encodes a putative leucine-rich repeat receptor protein kinase (LRR-RPK), and its expression is associated with the differentiation of the microsporocytes and tapetal cells, suggesting that EMS1 mediates signals that control the fate of reproductive cells and their contiguous somatic cells.
细胞分化对于多细胞生物体的发育至关重要。在开花植物中,单倍体雄配子体(花粉粒)在花药中由称为小孢子母细胞的生殖细胞产生。几种类型的体细胞确保花粉的成功发育,从而实现繁殖。然而,尚不清楚哪些基因调节花药中这些多样、高度特化细胞的分化。我们在此报告了一种新型拟南芥雄性不育突变体——过量小孢子母细胞1(ems1)的分离和特征,该突变体产生过量的小孢子母细胞,缺乏绒毡层细胞,并异常维持中层细胞。尽管ems1突变体中的减数分裂核分裂正常,但小孢子母细胞不进行胞质分裂,导致小孢子发生失败和雄性不育。EMS1基因编码一种假定的富含亮氨酸重复序列受体蛋白激酶(LRR-RPK),其表达与小孢子母细胞和绒毡层细胞的分化相关,这表明EMS1介导控制生殖细胞及其相邻体细胞命运的信号。