Eggshell Chitin and Chitin-Interacting Proteins Prevent Polyspermy in C. elegans
Eggshell Chitin and Chitin-Interacting Proteins Prevent Polyspermy in C. elegans
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DOI：
10.1016/j.cub.2010.09.059
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发表时间：
2010-11-09
期刊：
影响因子：
9.2
通讯作者：
Dennis, James W.
中科院分区：
文献类型：
--
作者：
Johnston, Wendy L.;Krizus, Aldis;Dennis, James W.
发育需要单个精子受精[1，2]。在秀丽隐杆线虫中，受精发生在充满精子的受精囊中，这意味着多精受精的障碍是在这个隔间中产生的。卵壳几丁质的合成始于受精，在受精卵离开受精囊之前沉积。然而多精受精在野生型中是非常罕见的，在这里，我们报告了14%-51%的受精卵由于失去几丁质合成酶-1（CHS-1）、CHS-1底物UDP-N-乙酰葡糖胺、CHS-1相互作用蛋白EGG-3或精子提供蛋白SPE-11而导致几丁质缺乏。spe-11（hc 90）突变体将几丁质沉积在雄性末端，但不能完成连续的层。多精受精屏障也受到几丁质结合蛋白CBD-1或GLD-1调节的LDL受体样EGG-1及其同源物EGG-2的损失的损害。CBD-1或EGG-1/2的缺失破坏了CHS-1以及MBK-2和EGG-3的卵母细胞皮质分布。在CBD-1或EGG-1/2缺乏时，几丁质合成，但蛋壳破裂，表明异常聚集的CHS-1/MBK-2/EGG-3可能无法支持连续蛋壳的构建。总之，我们的研究结果表明，蛋壳几丁质是防止C。elegans，除了其先前报道的极体挤出和受精卵极化的要求。
Development requires fertilization by a single sperm [1, 2]. In Caenorhabditis elegans, fertilization occurs in a sperm-filled spermatheca, implying the barrier to polyspermy is generated in this compartment. Eggshell chitin synthesis is initiated at fertilization, and chitin is deposited before the zygote exits the spermatheca. Whereas polyspermy is very rare in wild-type, here we report an incidence of 14%-51% in zygotes made chitin deficient by loss of chitin synthase-1 (CHS-1), the CHS-1 substrate UDP-N-acetylglucosamine, the CHS-1-interacting protein EGG-3, or the sperm-provided protein SPE-11. The spe-11(hc90) mutant deposits chitin at the male end but fails to complete a continuous layer. The polyspermy barrier is also compromised by loss of the chitin-binding protein CBD-1 or the GLD-1-regulated LDL receptor-like EGG-1, together with its homolog, EGG-2. Loss of CBD-1 or EGG-1/2 disrupts oocyte cortical distribution of CHS-1, as well as MBK-2 and EGG-3. In CBD-1 or EGG-1/2 deficiency, chitin is synthesized but the eggshell is fractured, suggesting aberrantly clustered CHS-1/MBK-2/EGG-3 may fail to support construction of a continuous eggshell. Together, our results show that eggshell chitin is required to prevent polyspermy in C. elegans, in addition to its previously reported requirement in polar body extrusion and polarization of the zygote.