| INTRODUCTION | 第8-9页 |
| GENERAL INTRODUCTION | 第9-14页 |
| CHAPTER 1:CELL POLARITY IN EUKAYOTES AND PROKARYOTES | 第14-59页 |
| 1. Mechanisms of cell polarization in eukaryotes | 第15-25页 |
| 1.1 Small GTPases of the Ras superfamily | 第15-18页 |
| 1.2 Cell polarization by small GTPases and their cognate GTPase activating proteins (GAP) | 第18-25页 |
| 1.2.1 Embryonic polarization in Caenorhabditis elegans | 第18-20页 |
| 1.2.2 Polarized positioning of budding site enabled by a Cdc42 GAP-mediatedinhibitory zone | 第20-22页 |
| 1.2.3 Directional polarization by chemotactic Dyctyostelium | 第22-25页 |
| 2. Cell polarity in bacteria | 第25-59页 |
| 2.1 Cell polarity in microbes:necessa ry or not? | 第25-26页 |
| 2.2 Mechanisms of specific protein localization during cell polarization | 第26-54页 |
| 2.2.1 Cell Polarization by membrane rafts | 第26-29页 |
| 2.2.2 Cell polarization by geometric recognition of curvature | 第29-32页 |
| 2.2.3 Cell polarization by cell wall biosynthesis | 第32-35页 |
| 2.2.4 Cell polarization by chromosomal polarity | 第35-39页 |
| 2.2.5 Role of the bacterial cytoskeleton in cell polarity | 第39-49页 |
| 2.2.5.1 FtsZ:the bacterial tubulin homologue | 第39-44页 |
| 2.2.5.1.1 Assembly of FtsZ at midcell | 第40-42页 |
| 2.2.5.1.2 Role of midcell positioning of FtsZ rings in cell polarization | 第42-43页 |
| 2.2.5.1.3 FtsZ dictates asymmetric cell division | 第43-44页 |
| 2.2.5.2 The role of the actin-like cytoskeleton in cell polarization | 第44-47页 |
| 2.2.5.3 Role of Intermediate filaments CreS in cell polarization | 第47-49页 |
| 2.2.6 Polar organizing factors | 第49-52页 |
| 2.2.7 Polar sensory systems | 第52-54页 |
| 2.3 Dynamic polarity regulation | 第54-59页 |
| 2.3.1 Two-component systems | 第54-57页 |
| 2.3.2 Two-component systems and the control of cell polarity: the example ofCtrA control during the Caulobacter cell cycle | 第57-58页 |
| 2.3.3 Dynamic polarity switching during Myxococcus xanthus motility | 第58-59页 |
| CHAPTER 2:DYNAMIC CELL POLARITY IN MYXOCOCCUS XANTHUS | 第59-75页 |
| 1. Motility mechanisms in Myxococcus xanthus | 第61-69页 |
| 1.1 Myxococcus motility is driven by two distinct macromolecular systems | 第61-69页 |
| 1.1.1 Twitching motility | 第61-64页 |
| 1.1.1.1 Type-Ⅳ pili drive twitching motility | 第61-62页 |
| 1.1.1.2 Twitching mechanism | 第62-64页 |
| 1.1.2 Gliding motility | 第64-69页 |
| 1.1.2.1 Gliding motility is powered by distributed motors | 第64-65页 |
| 1.1.2.2 The gliding motility machinery | 第65-69页 |
| 2. Spatial regulation of the motility systems by the Frz two-component system in Myxococcus xanthus | 第69-75页 |
| 2.1 Biased random walk by regulated cellular reversals? | 第69-70页 |
| 2.2 The Frz-signal transduction pathway | 第70-72页 |
| 2.2.1 Input into the Frz pathway | 第70-71页 |
| 2.2.2 Output from the Frz pathway | 第71-72页 |
| 2.3 Generating cellular reversals | 第72-73页 |
| 2.3.1 Twitching motility reversals | 第72页 |
| 2.3.2 Gliding motility reversals | 第72-73页 |
| 2.4 Coordinating cellular reversals | 第73-75页 |
| RESULTS | 第75-152页 |
| PART 1:DYNAMIC POLARITY SWITCH BY SMALL GTPASE IN M.XANTHUS | 第76-106页 |
| 1. MgIA is central regulator of dynamic reversals | 第77-106页 |
| ARTICLE 1 | 第79-106页 |
| PART 2.POLAR TARGETING OF THE MOTILITY PROTEINS | 第106-152页 |
| 2. RomR regulates the localization of MgIAB and may link MgIAB to Frz | 第107-152页 |
| ARTICLE 2 | 第110-152页 |
| DISCUSSION&PERSPECTIVE | 第152-166页 |
| 1. How does MgIA synchronize the two motility systems? | 第153-157页 |
| 1.1 The role of MgIA-GTP in cell motility | 第153页 |
| 1.2 How does MgIA activate motility? | 第153-155页 |
| 1.2.1 FrzS | 第153页 |
| 1.2.2 AgIZ | 第153-154页 |
| 1.2.3 Other downstream targets | 第154-155页 |
| 1.3 Synchronizing directionalities of both A- and S- motilities | 第155-156页 |
| 1.3.1 Directionality of S-motility | 第155页 |
| 1.3.2 Di rectionality of A-motility | 第155-156页 |
| 1.3.3 How to synchronize both motility systems? | 第156页 |
| 1.4 Future approaches to answer these questions | 第156-157页 |
| 2. How does a cell reverse? | 第157-163页 |
| 2.1 What elicits a cell reversal? | 第157页 |
| 2.2 An intricate localization interdependence network underlies the polarity axis | 第157-160页 |
| 2.2.1 FrzS and AgIZ act downstream from MgIA,B and RomR | 第158页 |
| 2.2.2 RomR,MgIB and MgIA regulate the polarity axis | 第158-160页 |
| 2.3 Reversal switch and linkage with the upstream frz pathway | 第160-161页 |
| 2.3.1 Role of RomR | 第160页 |
| 2.3.2 Role of FrzZ | 第160-161页 |
| 2.4 Current model of cell reversal and future questions to be add ressed | 第161-163页 |
| 3. Future challenges and questions related to motility regulation | 第163-166页 |
| 3.1 Integrated motility regulations in Myxococcus | 第163页 |
| 3.2 A conserved role of MglAB in bacterial polarity? | 第163-164页 |
| 3.3 Evolution of MgIAB regulation in Myxococcus | 第164页 |
| 3.4 Towards the understanding of multicellular behaviors in Myxococcus | 第164-166页 |
| APPENDICES | 第166-201页 |
| ARTICLE 3 | 第167-184页 |
| ARTICLE 4 | 第184-195页 |
| ARTICLE 5 | 第195-201页 |
| ACKNOWLEDGEMENTS | 第201-202页 |
| REFERENCES | 第202-220页 |
| Abstract | 第220页 |
| 学位论文评阅及答辩情况表 | 第221页 |
