Kapoor Sanjay, Takatsuji Hiroshi
Developmental Biology Laboratory, Plant Physiology Department, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba 305-8602, Ibaraki, Japan.
Plant Mol Biol. 2006 Jun;61(3):415-30. doi: 10.1007/s11103-006-0020-0.
MEZ1 (MEiosis-associated Zinc-finger protein 1) was first isolated as an anther-specific cDNA from Petunia hybrida. In the present study, we report its functional characterization, including its spatial and temporal expression profiles and phenotypes in MEZ1-silenced plants. MEZ1 transcripts were specifically localized in pollen mother cells during early stages of anther development, and were later distributed in vegetative tissues in anthers. Silencing of MEZ1 by cosuppression resulted in several anomalies during male meiosis that included inability of chromosomes to condense, loss of meiotic synchrony, and premature and apparently uncontrolled cytokinetic events. Consequently, by the end of meiosis 8-10 cells, instead of the normal 4, with varying DNA contents were formed in the MEZ1-silenced meiocytes. Most of these aborted prematurely, and those that matured had a distinctive morphology. MEZ1-silenced plants were female sterile when pollinated with wild-type pollen but they infrequently produced a few seeds upon self-pollination. Resulting T1 plants had increased ploidy levels and exhibited severe anomalies during male meiosis, rendering them completely sterile. We discuss possible role of MEZ1 in the proper progression of plant meiosis.
MEZ1（减数分裂相关锌指蛋白1）最初是从矮牵牛中分离得到的一种花药特异性cDNA。在本研究中，我们报告了其功能特征，包括其在花药发育早期的时空表达谱以及MEZ1沉默植株的表型。MEZ1转录本在花药发育早期特异性定位于花粉母细胞中，随后分布于花药的营养组织中。通过共抑制使MEZ1沉默导致雄性减数分裂过程中出现多种异常，包括染色体无法浓缩、减数分裂同步性丧失以及过早且明显不受控制的细胞分裂事件。因此，在减数分裂结束时，MEZ1沉默的减数分裂细胞中形成了8 - 10个细胞，而非正常的4个细胞，且DNA含量各异。其中大多数细胞过早败育，而那些成熟的细胞具有独特的形态。用野生型花粉授粉时，MEZ1沉默的植株雌性不育，但自花授粉时偶尔会产生少量种子。产生的T1代植株倍性水平增加，并且在雄性减数分裂过程中表现出严重异常，使其完全不育。我们讨论了MEZ1在植物减数分裂正常进程中的可能作用。
