N-linked glycosylation of proteins is the most common post-translational modification of proteins. The enzyme UDP-N-acetylglucosamine-dolichyl-phosphate N-acetylglucosaminephosphotransferase (DPAGT1) catalyses the first step of N-glycosylation, and DPAGT1 knockout is embryonic lethal in mice. In this study, we identified the sole orthologue (algn-7) of the human DPAGT1 in the nematode C. elegans. The gene activity was disrupted by RNAi and deletion mutagenesis, which resulted in larval lethality, defects in oogenesis and oocyte-to-embryo transition. Endomitotic oocytes, abnormal fusion of pronuclei, abnormal AB cell rotation, disruption of permeation barriers of eggs, and abnormal expression of chitin and chitin synthase in oocytes and eggs were the typical phenotypes observed. The results indicate that N-glycosylation is indispensable for these processes. We further screened an N-glycosylated protein database of C. elegans, and identified 456 germline-expressed genes coding N-glycosylated proteins. By examining RNAi phenotypes, we identified five germline-expressed genes showing similar phenotypes to the algn-7 (RNAi) animals. They were ribo-1, stt-3, ptc-1, ptc-2, and vha-19. We identified known congenital disorders of glycosylation (CDG) genes (ribo-1 and stt-3) and a recently found CDG gene (vha-19). The results show that phenotype analyses using the nematode could be a powerful tool to detect new CDG candidate genes and their associated gene networks.

中文翻译：

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UDP- Ñ乙酰氨基葡萄糖-多萜醇基磷酸盐Ñ -acetylglucosaminephosphotransferase为卵子发生不可缺少的，卵母细胞对胚胎的过渡，和线虫的幼虫发育线虫

蛋白质的N-联糖基化是蛋白质最常见的翻译后修饰。酶UDP- Ñ乙酰氨基葡萄糖-多萜醇基磷酸盐Ñ -acetylglucosaminephosphotransferase（DPAGT1）催化的第一个步骤Ñ -glycosylation，和DPAGT1敲除是胚胎致死小鼠。在这项研究中，我们确定了线虫秀丽隐杆线虫中人DPAGT1的唯一直系同源物（algn-7）。。RNAi和缺失诱变破坏了基因活性，导致幼虫杀伤力，卵子发生缺陷和卵母细胞向胚胎的转化。观察到的典型表型为内吞有卵母细胞，核的融合异常，AB细胞旋转异常，卵的渗透屏障破坏以及甲壳质和甲壳质合酶的异常表达。结果表明，N-糖基化对于这些过程是必不可少的。我们进一步筛选了秀丽隐杆线虫的N-糖基化蛋白数据库，并鉴定了456个种系表达的编码N-糖基化蛋白的基因。通过检查RNAi表型，我们鉴定了5个种系表达基因，它们显示出与表型相似的表型。algn-7（RNAi）动物。它们是ribo-1，stt-3，ptc-1，ptc-2和vha-19。我们确定了已知的先天性糖基化（CDG）基因（ribo-1和stt-3）和最近发现的CDG基因（vha-19）。结果表明，使用线虫进行表型分析可能是检测新的CDG候选基因及其相关基因网络的有力工具。