Screening for putative kinases or phosphatases affecting intraflagellar transport and ciliobiogenesis in C. elegans

• Main Authors: Hsieh, Jung, 謝榕
• Other Authors: Wagner, Oliver
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/25500919766733638257

碩士 === 國立清華大學 === 分子與細胞生物研究所 === 100 === 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.