ACT-5 is an essential Caenorhabditis elegans actin required for intestinal microvilli formation
ACT-5 is an essential Caenorhabditis elegans actin required for intestinal microvilli formation
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DOI：
10.1091/mbc.e04-12-1061
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发表时间：
2005-07-01
影响因子：
3.3
通讯作者：
Waddle, JA
中科院分区：
文献类型：
--
作者：
MacQueen, AJ;Baggett, JJ;Waddle, JA
对秀丽隐杆线虫act-5基因功能的研究表明，肠微绒毛的形成需要一种特定的肌动蛋白亚型。ACT-5是五个C中分歧最大的。elegans actins，与其他四个只有93%的同一性。绿色荧光蛋白报告和免疫荧光分析表明，ACT-5基因的表达是有限的微绒毛细胞内的肠和排泄系统和ACT-5是顶部定位在肠细胞内。显性act-5突变的杂合子动物看起来又瘦又清，生长缓慢。显性act-5突变或隐性功能丧失突变的纯合子动物表现出正常的形态和肠细胞极性，但在第一个幼虫阶段死亡。超微结构分析显示纯合act-5突变体的肠微绒毛完全丧失。在act-5启动子的控制下强制表达ACT-1并不能挽救act-5突变体的致死性。连同免疫电子显微镜实验表明ACT-5在微绒毛本身内富集，这些结果表明ACT-5具有微绒毛特异性功能，并且进一步地，它们提高了特定肌动蛋白可能专门用于构建微绒毛和相关结构的可能性。
Investigation of Caenorhabditis elegans act-5 gene function revealed that intestinal microvillus formation requires a specific actin isoform. ACT-5 is the most diverged of the five C. elegans actins, sharing only 93% identity with the other four. Green fluorescent protein reporter and immunofluorescence analysis indicated that act-5 gene expression is limited to microvillus-containing cells within the intestine and excretory systems and that ACT-5 is apically localized within intestinal cells. Animals heterozygous for a dominant act-5 mutation looked clear and thin and grew slowly. Animals homozygous for either the dominant act-5 mutation, or a recessive loss of function mutant, exhibited normal morphology and intestinal cell polarity, but died during the first larval stage. Ultrastructural analysis revealed a complete loss of intestinal microvilli in homozygous act-5 mutants. Forced expression of ACT-1 under the control of the act-5 promoter did not rescue the lethality of the act-5 mutant. Together with immuno-electron microscopy experiments that indicated ACT-5 is enriched within microvilli themselves, these results suggest a microvillus-specific function for act-5, and further, they raise the possibility that specific actins may be specialized for building microvilli and related structures.