Functional domains and temperature-sensitive mutations in SPE-9, an EGF repeat-containing protein required for fertility in Caenorhabditis elegans.
Functional domains and temperature-sensitive mutations in SPE-9, an EGF repeat-containing protein required for fertility in Caenorhabditis elegans.
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SPE-9 的功能域和温度敏感突变，SPE-9 是秀丽隐杆线虫生育所需的含有 EGF 重复序列的蛋白质。
DOI：
10.1016/j.ydbio.2004.05.014
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Singson,Andrew
中科院分区：
文献类型：
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作者：
Putiri,Emily;Zannoni,Sonia;Kadandale,Pavan;Singson,Andrew
Spe-9基因是秀丽线虫生育所必需的，它编码一种带有胞外区(ECD)的精子跨膜蛋白，其中包含10个表皮生长因子(EGF)重复序列。缺失分析表明，EGF重复和跨膜结构域是受精所必需的。相反，SPE-9的细胞质区域并不是受精所必需的。所有10个EGF基序中的个别点突变揭示了这些序列对改变的不同敏感性。一些EGF重复序列不能容忍突变，导致完全缺乏生育能力。其他EGF重复序列可以突变以创造具有温度敏感型(Ts)生育表型的动物。所有TS突变都是通过改变EGF基序中保守的半胱氨酸或甘氨酸残基而产生的。对于Spe-9的两个内源性ts等位基因，在不允许的温度下功能丧失不是由于蛋白质错误定位或降解造成的。此外，SPE-9在精子中的正确定位在遗传交互作用的生育突变(SPE-13)或影响精子囊-质膜融合的突变(FER-1)中没有改变。与Notch/LIN-12/GLP-1受体及其配体中的EGF重复序列一样，SPE-9中的EGF重复序列可能具有不同的功能。由于在不同物种的许多蛋白质中都发现了EGF基序，类似的实验策略可以用来在其他含有EGF基序的分子中产生有用的温度敏感突变。
The spe-9 gene is required for fertility in Caenorhabditis elegans and encodes a sperm transmembrane protein with an extracellular domain (ECD) that contains 10 epidermal growth factor (EGF) repeats. Deletion analysis reveals that the EGF repeats and the transmembrane domain are required for fertilization. In contrast, the cytoplasmic region of SPE-9 is not essential for fertilization. Individual point mutations in all 10 EGF motifs uncover a differential sensitivity of these sequences to alteration. Some EGF repeats cannot tolerate mutation leading to a complete lack of fertility. Other EGF repeats can be mutated to create animals with temperature-sensitive (ts) fertility phenotypes. All ts mutations were generated by changing either conserved cysteine or glycine residues in the EGF motifs. For two endogenous ts alleles of spe-9, loss of function at nonpermissive temperatures is not due to protein mislocalization or degradation. Additionally, the proper localization of SPE-9 in sperm is not altered in a genetically interacting fertility mutant (spe-13) or a mutant that affects sperm vesicle-plasma membrane fusion (fer-1). Like the EGF repeats in the Notch/LIN-12/GLP-1 receptors and their ligands, the EGF repeats in SPE-9 may carry out different functions. Because EGF motifs are found in many proteins in different species, similar experimental strategies could be used to generate useful temperature-sensitive mutations in other EGF motif-containing molecules.