纖毛為細胞表面延伸之次級結構，常見於絕大多數原核及真核生物細胞，且依功能性分為初級纖毛及鞭毛，分別用於感應刺激及細胞運動。初級纖毛可感知環境刺激，藉以調控眾多細胞生理機能，許多知名的纖毛病變例如成人型多囊性腎病、先天性纖毛運動異常症、巴德-畢德氏症候群、美-格二氏綜合症及腎臟消耗病。纖毛內運輸(IFT)為纖毛生成最主要的分子機制，也調控大部分之纖毛內訊號傳遞路徑。蛋白激酶及磷酸酶對細胞訊號傳遞及分子運動的影響甚鉅，過去曾有研究證實MAP蛋白激酶、CDK相關激酶和PI 5-磷酸酶會藉纖毛內運輸機制影響纖毛生成，因此本篇論文以線蟲作為模式生物，探討特定蛋白激酶及磷酸酶對初級纖毛結構的影響。我們用一已知的纖毛基因啟動子X-box作為分子標誌，結合生物資訊工具，找出若干可能的蛋白激酶及磷酸酶基因，並利用基因轉殖技術結合螢光蛋白與纖毛內運輸機制相關之蛋白質，藉此觀察特定基因缺陷是否會影響纖毛生成及其運輸機制。我們利用RNAi及雜交技術控制螢光轉殖線蟲的基因表現，並觀察在各式不同蛋白激酶或磷酸酶的缺失之下，纖毛內運輸蛋白OSM-3、KAP-1、CHE-11及XBX-1組成之纖毛結構及分子運動情形，以鑑別此類基因是否會影響初級纖毛生成。本篇論文發現兩種蛋白激酶基因dyf-18及pkg-1 可能影響纖毛內運輸機制，實驗結果顯示若缺乏此二基因將降低線蟲對特定化學嗅覺的刺激、改變部分纖毛運輸蛋白移動速度及位置。在本篇論文結論中，我們發現若干蛋白激酶可能改變纖毛結構及其內分子運輸機制，但其詳細機制仍需待後續研究繼續探討。

Cilia are specialized subcellular organelles that project from various cell types in most eukaryotic organisms. Non-motile cilia, or primary cilia, are mainly responsible for sensory function and are recognized to have essential roles in physiology and development. As basic and highly conserved structures, cilia are also implicated in numbers of severe disorders termed ciliopathies. Examples of cilia-based human diseases are Adult polycystic kidney disease (APKD), Bardet-Biedl syndrome (BBS), Meckel-Gruber syndrome (MKS) and nephronophthisis. The intraflagellar transport (IFT) mechanism is fundamentally involved in cilia assemby and coupled with multiple intracellular signaling pathways. Importantly, previous studies revealed critical roles of a MAP kinase, a CDK-related kinase and a PI 5-phosphatase involved in IFT regulation. To identify more essential kinases or phosphatases involved in these processes, we screened for certain candidates specifically carrying the X-Box promoter motif, known to be an indicator for genes solely expressed in cilia. Using the model organism C. elegans, we screened for a dozen putative kinases and phosphatase that may affect structural intactness and basic chemosensation ability of sensory neurons as well as affect IFT. Here we employed either crossing of existing IFT reporter strains with mutant strains or by employing RNAi on the IFT wild type reporter strains. In detail, we analyzed ciliary expression pattern and motility of diverse IFT complexes, including two anterograde motors kinesin-II and OSM-3 kinesin, retrograde motor IFT-dynein, and a specific IFT complex subunit. In this study, we identified a putative novel regulator of ciliogenesis and IFT transport: the cyclic GMP-dependent protein kinase PKG-1. This enzyme causes a delayed reaction for sensing chemoattractants, alters IFT-particle localization pattern and slowed down the transport velocity of several IFT particles in the distal part of the cilia. Together, we suggest that PKG-1 may be required for proper localization and transport of IFT components in C elegans sensory cilia.

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