The twisted pharynx phenotype in C. elegans.
The twisted pharynx phenotype in C. elegans.
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DOI：
10.1186/1471-213x-7-61
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发表时间：
2007-06-01
影响因子：
--
通讯作者：
Pilon M
中科院分区：
文献类型：
--
作者：
Axäng C;Rauthan M;Hall DH;Pilon M
线虫的咽部是一种上皮管，其发育可与胚胎心脏和肾脏的发育进行比较，因此可作为器官发育的有趣模型。据报道，几种秀丽隐杆线虫突变体表现出扭曲的咽表型，但尚未进行仔细的研究来直接解决这一现象。在这项研究中，详细检查了扭曲突变体 dig-1、mig-4、mnm-4 和 unc-61，并研究了扭曲的性质。我们发现，扭曲表型在整个幼虫发育过程中恶化，在大多数突变体中，当从蠕虫体解剖时，咽部保留其扭曲，并且mnm-4和具有增厚咽结构域的突变体（pha-2和sma-1）之间的双突变体在这些区域中的扭曲较少。我们还描述了连接咽基底层和体壁的咽腱器官的超微结构，并表明这些腱器官被扭曲的咽部拉成螺旋方向。在扭曲的咽部内，肌动蛋白丝也显示出扭曲，并且比对照组更长。在粘附分子突变体的小型筛选中，我们还鉴定了另一种扭曲咽突变体，sax-7。咽部细胞骨架长度或其细胞外基质锚定点的缺陷被认为是扭转力的实际来源。对于细胞外粘附或器官附着所需的基因，以及可能对于细胞骨架调节所需的基因来说，扭曲的咽是一种有用且易于评分的表型。
The pharynx of C. elegans is an epithelial tube whose development has been compared to that of the embryonic heart and the kidney and hence serves as an interesting model for organ development. Several C. elegans mutants have been reported to exhibit a twisted pharynx phenotype but no careful studies have been made to directly address this phenomenon. In this study, the twisting mutants dig-1, mig-4, mnm-4 and unc-61 are examined in detail and the nature of the twist is investigated. We find that the twisting phenotype worsens throughout larval development, that in most mutants the pharynx retains its twist when dissected away from the worm body, and that double mutants between mnm-4 and mutants with thickened pharyngeal domains (pha-2 and sma-1) have less twisting in these regions. We also describe the ultrastructure of pharyngeal tendinous organs that connect the pharyngeal basal lamina to that of the body wall, and show that these are pulled into a spiral orientation by twisted pharynges. Within twisted pharynges, actin filaments also show twisting and are longer than in controls. In a mini screen of adhesionmolecule mutants, we also identified one more twisting pharynx mutant, sax-7. Defects in pharyngeal cytoskeleton length or its anchor points to the extracellular matrix are proposed as the actual source of the twisting force. The twisted pharynx is a useful and easy-to-score phenotype for genes required in extracellular adhesion or organ attachment, and perhaps forgenes required for cytoskeleton regulation.