KLU suppresses megasporocyte cell fate through SWR1-mediated activation of WRKY28 expression in Arabidopsis
KLU suppresses megasporocyte cell fate through SWR1-mediated activation of WRKY28 expression in Arabidopsis
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在拟南芥中，KLU 通过 SWR1 介导的 WRKY28 表达激活来抑制大孢子母细胞的命运。
DOI：
10.1073/pnas.1716054115
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发表时间：
2018-01-16
影响因子：
11.1
通讯作者：
Qin, Yuan
中科院分区：
文献类型：
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作者：
Zhao, Lihua;Cai, Hanyang;Qin, Yuan
意义 在开花植物中，雌性生殖系始于每个胚珠中的单个细胞，称为大孢子母细胞 (MMC)。将 MMC 命运限制在单个细胞上的机制仍然很大程度上未知。我们发现拟南芥细胞色素 P450 基因 KLU 通过染色质重塑复合物 SWR1 发挥作用，促进胚珠原基中 WRKY28 的表达。我们发现 WRKY28 在 MMC 周围的一些体细胞中表达，并且是抑制这些细胞获得类似 MMC 细胞命运所必需的。与非细胞自主 KLU 活性一致，KLU 表达细胞和 WRKY28 表达细胞既不相同也不相邻。我们的研究表明，仅涉及胚珠原基中体细胞的细胞间相互作用确保了单个 MMC 的规范。种系规范对于有性生殖至关重要。在大多数开花植物的胚珠中，只有一个皮下细胞放大并分化为大孢子母细胞（MMC），即雌性种系谱系的创始细胞。将 MMC 规范限制在单个细胞的分子机制仍然难以捉摸。我们发现拟南芥转录因子 WRKY28 只在 MMC 周围的皮下体细胞中表达，并且需要抑制这些细胞获得类似 MMC 的细胞身份。在此过程中，SWR1 染色质重塑复合物介导组蛋白变体 H2A.Z 在 WRKY28 位点的掺入。此外，在内珠被原基中表达的细胞色素P450基因KLU通过H2A.Z沉积在WRKY28上，非细胞自主地促进WRKY28表达。总而言之，我们的研究结果表明，胚珠原基中的体细胞如何协同利用染色质重塑来将生殖系细胞规范限制为单个细胞。
Significance In flowering plants, the female germ line begins as a single cell known as the megaspore mother cell (MMC) in each ovule. The mechanisms that restrict MMC fate to a single cell remain largely unknown. We show that the Arabidopsis cytochrome P450 gene KLU acts through the chromatin remodeling complex SWR1 to promote WRKY28 expression in ovule primordia. We show that WRKY28 is expressed in a few somatic cells surrounding the MMC and is required to inhibit these cells from acquiring the MMC-like cell fate. Consistent with non–cell-autonomous KLU activity, KLU-expressing cells and WRKY28-expressing cells are neither identical nor adjacently positioned. Our study demonstrates that cell–cell interactions involving only somatic cells in ovule primordia ensure the specification of a single MMC. Germ-line specification is essential for sexual reproduction. In the ovules of most flowering plants, only a single hypodermal cell enlarges and differentiates into a megaspore mother cell (MMC), the founder cell of the female germ-line lineage. The molecular mechanisms restricting MMC specification to a single cell remain elusive. We show that the Arabidopsis transcription factor WRKY28 is exclusively expressed in hypodermal somatic cells surrounding the MMC and is required to repress these cells from acquiring MMC-like cell identity. In this process, the SWR1 chromatin remodeling complex mediates the incorporation of the histone variant H2A.Z at the WRKY28 locus. Moreover, the cytochrome P450 gene KLU, expressed in inner integument primordia, non–cell-autonomously promotes WRKY28 expression through H2A.Z deposition at WRKY28. Taken together, our findings show how somatic cells in ovule primordia cooperatively use chromatin remodeling to restrict germ-line cell specification to a single cell.