Yukita Akira, Michiue Tatsuo, Danno Hiroki, Asashima Makoto
Department of Life Sciences (Biology), Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan.
Dev Dyn. 2007 Oct;236(10):2757-66. doi: 10.1002/dvdy.21297.
The small ubiquitin-related modifier (SUMO) is a member of the ubiquitin-like protein family, and SUMO conjugation (SUMOylation) resembles ubiquitination. Despite many SUMOylation target proteins being reported, the role of this system in vertebrate development remains unclear. We inhibited the function of Xenopus SUMO-1 (XSUMO-1) using a morpholino antisense oligo against XSUMO-1 (XSUMO-1-MO) to clarify the role of SUMOylation. XSUMO-1-MO inhibited normal axis formation in embryos and elongation of activin-treated animal caps. The expression of several mesoderm markers was reduced by XSUMO-1-MO. We measured activin-like activity by using a reporter construct containing a multimer of activin-responsive elements from the Goosecoid promoter, [DE(6x)Luc]. This assay showed that XSUMO-1-MO directly inhibited activin/nodal signaling. Furthermore, XSUMO-1-MO inhibited ectopic axis formation induced by XSmad2, and XSmad2/4 mRNA could not rescue the axis elongation defect induced by XSUMO-1-MO. These results suggested that XSUMO-1 is required for normal axis elongation, at least partly mediating activin/nodal signaling.
小泛素相关修饰物（SUMO）是类泛素蛋白家族的成员，SUMO缀合（SUMO化）类似于泛素化。尽管已报道了许多SUMO化靶蛋白，但该系统在脊椎动物发育中的作用仍不清楚。我们使用针对非洲爪蟾SUMO-1（XSUMO-1）的吗啉代反义寡核苷酸（XSUMO-1-MO）抑制XSUMO-1的功能，以阐明SUMO化的作用。XSUMO-1-MO抑制胚胎中的正常轴形成以及激活素处理的动物帽的伸长。几种中胚层标志物的表达被XSUMO-1-MO降低。我们通过使用含有来自鹅膏蕈氨酸启动子的激活素反应元件多聚体的报告构建体[DE(6x)Luc]来测量激活素样活性。该试验表明XSUMO-1-MO直接抑制激活素/节点信号传导。此外，XSUMO-1-MO抑制由XSmad2诱导的异位轴形成，并且XSmad2/4 mRNA不能挽救由XSUMO-1-MO诱导的轴伸长缺陷。这些结果表明，XSUMO-1是正常轴伸长所必需的，至少部分介导激活素/节点信号传导。
