COPI Vesicle Transport Is a Common Requirement for Tube Expansion in Drosophila
COPI Vesicle Transport Is a Common Requirement for Tube Expansion in Drosophila
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DOI：
10.1371/journal.pone.0001964
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发表时间：
2008-04-09
期刊：
影响因子：
3.7
通讯作者：
Samakovlis, Christos
中科院分区：
文献类型：
--
作者：
Jayaram, Satish Arcot;Senti, Kirsten-Andre;Samakovlis, Christos
背景：管扩张缺陷，如狭窄和闭锁，会导致毁灭性的人类疾病。器官发生过程中的管腔扩张开始在几个系统中被阐明，但我们仍然缺乏对许多器官中这一过程的机械论观点。果蝇的气管呼吸系统为研究管子大小调节提供了一个顺从的模型。在气管中，腔蛋白的COPII顺行转运是细胞外基质组装和同时扩张气管所必需的。主要发现：我们鉴定并分析了具有狭窄气管的果蝇COPI逆行转运突变体。在气管扩张过程中，Gamma COP突变体不能有效地分泌管腔成分并组装管腔几丁质基质。同样，唾液腺的管状延长也是有缺陷的，这也与腔内沉积和组装不同的、瞬时的腔内基质的失败相吻合。果蝇Gamma CoP与顺式高尔基体标记共存，在Gamma CoP突变胚胎中，ER和高尔基体结构严重破坏。对γ-COP和Sar1双突变体的分析表明，双向ER-高尔基体运输维持内质网和高尔基体，是管腔基质分泌和组装所必需的。结论/意义：我们的结果证实了COPI组分在器官形态发生中的作用，并强调了顶端分泌和瞬时器官型基质组装在管扩张中的共同作用。已经在海鞘动物的脊索中检测到管腔内基质，斑马鱼COPI突变体在脊索扩张方面显示出缺陷。因此，不同管腔霉菌的程序性沉积和生长可能在不同器官的管子扩张过程中提供膨胀力。
Background: Tube expansion defects like stenoses and atresias cause devastating human diseases. Luminal expansion during organogenesis begins to be elucidated in several systems but we still lack a mechanistic view of the process in many organs. The Drosophila tracheal respiratory system provides an amenable model to study tube size regulation. In the trachea, COPII anterograde transport of luminal proteins is required for extracellular matrix assembly and the concurrent tube expansion.Principal Findings: We identified and analyzed Drosophila COPI retrograde transport mutants with narrow tracheal tubes. gamma COP mutants fail to efficiently secrete luminal components and assemble the luminal chitinous matrix during tracheal tube expansion. Likewise, tube extension is defective in salivary glands, where it also coincides with a failure in the luminal deposition and assembly of a distinct, transient intraluminal matrix. Drosophila gamma COP colocalizes with cis-Golgi markers and in gamma COP mutant embryos the ER and Golgi structures are severely disrupted. Analysis of gamma COP and Sar1 double mutants suggests that bidirectional ER-Golgi traffic maintains the ER and Golgi compartments and is required for secretion and assembly of luminal matrixes during tube expansion.Conclusions/Significance: Our results demonstrate the function of COPI components in organ morphogenesis and highlight the common role of apical secretion and assembly of transient organotypic matrices in tube expansion. Intraluminal matrices have been detected in the notochord of ascidians and zebrafish COPI mutants show defects in notochord expansion. Thus, the programmed deposition and growth of distinct luminal molds may provide distending forces during tube expansion in diverse organs.