Controlled Enlargement of the Glycoprotein Vesicle Surrounding a Volvox Embryo Requires the InvB Nucleotide-Sugar Transporter and Is Required for Normal Morphogenesis[W]
Controlled Enlargement of the Glycoprotein Vesicle Surrounding a Volvox Embryo Requires the InvB Nucleotide-Sugar Transporter and Is Required for Normal Morphogenesis[W]
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DOI：
10.1105/tpc.109.066159
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发表时间：
2009-04
期刊：
影响因子：
--
通讯作者：
N. Ueki;I. Nishii
中科院分区：
文献类型：
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作者：
N. Ueki;I. Nishii
在这里，我们报告了我们的分析团藻卡特，InvB，其胚胎不能执行反转，在这个过程中，每个团藻胚胎通常把自己的内翻在胚胎发生结束，从而实现成人配置的突变。invB基因编码核苷酸-糖转运蛋白，当在酵母中表达时，其表现出GDP-甘露糖转运活性。在野生型胚胎中，invB转录本在倒位之前和倒位期间最丰富。甘露糖苷探针（荧光伴刀豆球蛋白A）染色的糖蛋白丰富的gonidial囊泡（GV）周围的野生型胚胎比它染色的GV周围InvB胚胎更强烈。直接测量显示，在整个胚胎发生过程中，野生型胚胎周围的GV比InvB胚胎周围的GV在尺寸上增加得多，并且完全切割的InvB胚胎比野生型胚胎在其GV内更紧密地包装。为了检验由小于正常GV施加的限制直接导致突变体中的倒位缺陷的假设，我们通过显微手术将InvB胚胎从其GV中释放出来。由此产生的胚胎正常翻转，表明GV的受控扩大，通过需要InvB核苷酸-糖转运蛋白的过程，是为胚胎提供足够空间以完成翻转所必需的。
Here, we report our analysis of a mutant of Volvox carteri, InvB, whose embryos fail to execute inversion, the process in which each Volvox embryo normally turns itself inside-out at the end of embryogenesis, thereby achieving the adult configuration. The invB gene encodes a nucleotide-sugar transporter that exhibits GDP-mannose transport activity when expressed in yeast. In wild-type embryos, the invB transcript is maximally abundant before and during inversion. A mannoside probe (fluorescent concanavalin A) stains the glycoprotein-rich gonidial vesicle (GV) surrounding wild-type embryos much more strongly than it stains the GV surrounding InvB embryos. Direct measurements revealed that throughout embryogenesis the GV surrounding a wild-type embryo increases in size much more than the GV surrounding an InvB embryo does, and the fully cleaved InvB embryo is much more tightly packed within its GV than a wild-type embryo is. To test the hypothesis that the restraint imposed by a smaller than normal GV directly causes the inversion defect in the mutant, we released InvB embryos from their GVs microsurgically. The resulting embryos inverted normally, demonstrating that controlled enlargement of the GV, by a process in which requires the InvB nucleotide-sugar transporter, is essential to provide the embryo sufficient space to complete inversion.