Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA.
Mol Plant. 2008 Jul;1(4):620-33. doi: 10.1093/mp/ssn030. Epub 2008 Jun 26.
The Arabidopsis dsy10 mutant was previously identified as being defective in the synapsis of meiotic chromosomes resulting in male and female sterility. We report here the molecular analysis of the mutation and show that it represents a T-DNA insertion in the third exon of the SWI1 gene. Four mutations have now been identified in SWI1, several of which exhibit different phenotypes. For example, the swi1-1 and dyad mutations only affect meiosis in megasporocytes, while the swi1-2 and dsy10 mutations block both male and female meiosis. Furthermore, as part of a detailed cytological characterization of dsy10 meiocytes, we identified several differences during male meiosis between the swi1-2 and dys10 mutants, including variations in the formation of axial elements, the distribution of cohesin proteins and the timing of the premature loss of sister chromatid cohesion. We demonstrate that dsy10 represents a complete loss-of-function mutation, while a truncated form of SWI1 is expressed during meiosis in swi1-2 plants. We further show that dys10 meiocytes exhibit alterations in modified histone patterns, including acetylated histone H3 and dimethylated histone H3-Lysine 4.
拟南芥 dysy10 突变体先前被鉴定为在减数分裂染色体联会过程中存在缺陷，导致雄性和雌性不育。我们在此报告该突变的分子分析结果，并表明它代表 SWI1 基因第三外显子中的 T-DNA 插入。现在已经在 SWI1 中鉴定出了四个突变，其中几个表现出不同的表型。例如，swi1-1 和 dyad 突变仅影响大孢子母细胞的减数分裂，而 swi1-2 和 dysy10 突变则阻断了雄性和雌性减数分裂。此外，作为对 dysy10 减数分裂细胞进行详细细胞学特征描述的一部分，我们在 swi1-2 和 dysy10 突变体的雄性减数分裂过程中鉴定出了几个差异，包括轴丝形成、黏合蛋白的分布和姐妹染色单体过早失去黏合的时间变化。我们证明 dysy10 代表完全功能丧失突变，而 swi1-2 植物减数分裂期间表达了 SWI1 的截断形式。我们进一步表明 dysy10 减数分裂细胞表现出修饰组蛋白模式的改变，包括乙酰化组蛋白 H3 和组蛋白 H3-赖氨酸 4 的二甲基化。
