The Boyce Thompson Institute, 533 Tower Road, Ithaca, NY 14853, USA.
J Exp Bot. 2023 Sep 29;74(18):5500-5513. doi: 10.1093/jxb/erad294.
The nuclear lamina in plant cells is composed of plant-specific proteins, including nuclear matrix constituent proteins (NMCPs), which have been postulated to be functional analogs of lamin proteins that provide structural integrity to the organelle and help stabilize the three-dimensional organization of the genome. Using genomic editing, we generated alleles for the three genes encoding NMCPs in cultivated tomato (Solanum lycopersicum) to determine if the consequences of perturbing the nuclear lamina in this crop species were similar to or distinct from those observed in the model Arabidopsis thaliana. Loss of the sole NMCP2-class protein was lethal in tomato but is tolerated in Arabidopsis. Moreover, depletion of NMCP1-type nuclear lamina proteins leads to distinct developmental phenotypes in tomato, including leaf morphology defects and reduced root growth rate (in nmcp1b mutants), compared with cognate mutants in Arabidopsis. These findings suggest that the nuclear lamina interfaces with different developmental and signaling pathways in tomato compared with Arabidopsis. At the subcellular level, however, tomato nmcp mutants resembled their Arabidopsis counterparts in displaying smaller and more spherical nuclei in differentiated cells. This result argues that the plant nuclear lamina facilitates nuclear shape distortion in response to forces exerted on the organelle within the cell.
植物细胞的核层由植物特异性蛋白组成，包括核基质组成蛋白（NMCPs），它们被假定为 lamin 蛋白的功能类似物，为细胞器提供结构完整性，并有助于稳定基因组的三维组织。我们使用基因组编辑生成了栽培番茄（Solanum lycopersicum）中编码 NMCPs 的三个基因的等位基因，以确定在这种作物物种中扰乱核层的后果是否与在模式植物拟南芥中观察到的相似或不同。在番茄中，唯一的 NMCP2 类蛋白的缺失是致命的，但在拟南芥中是可以耐受的。此外，与拟南芥的同源突变体相比，NMCP1 型核层蛋白的耗竭导致番茄出现不同的发育表型，包括叶片形态缺陷和根生长速率降低（在 nmcp1b 突变体中）。这些发现表明，与拟南芥相比，核层在番茄中与不同的发育和信号通路相互作用。然而，在亚细胞水平上，与拟南芥的 NMCP 突变体相比，番茄 nmcp 突变体在分化细胞中表现出更小和更球形的核，这表明植物核层有助于核形状在细胞器受到细胞内力作用时发生扭曲。
