| 1. |
|
|
| 2. |
- Burghoorn, J, et al.
(författare)
-
Dauer pheromone and G-protein signaling modulate the coordination of intraflagellar transport kinesin motor proteins in C. elegans
- 2010
-
Ingår i: Journal of cell science. - : The Company of Biologists. - 1477-9137 .- 0021-9533. ; 123:12Pt 12, s. 2076-2083
-
Tidskriftsartikel (refereegranskat)abstract
- Cilia length and function are dynamically regulated by modulation of intraflagellar transport (IFT). The cilia of C. elegans amphid channel neurons provide an excellent model to study this process, since they use two different kinesins for anterograde transport: kinesin-II and OSM-3 kinesin together in the cilia middle segments, but only OSM-3 in the distal segments. To address whether sensory signaling modulates the coordination of the kinesins, we studied IFT protein motility in gpa-3 mutant animals, since dominant active mutation of this sensory Gα protein GPA-3QL) affects cilia length. In addition, we examined animals exposed to dauer pheromone, since dauer formation, which involves gpa-3, induces changes in cilia morphology. Live imaging of fluorescently tagged IFT proteins showed that in gpa-3 mutants and in larvae exposed to dauer pheromone, kinesin-II speed is decreased and OSM-3 speed is increased, whereas structural IFT proteins move at an intermediate speed. These results indicate that mutation of gpa-3 and exposure to dauer pheromone partially uncouple the two kinesins. We propose a model in which GPA-3-regulated docking of kinesin-II and/or OSM-3 determines entry of IFT particles into the cilia subdomains, allowing structural and functional plasticity of cilia in response to environmental cues.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Piasecki, BP, et al.
(författare)
-
Regulatory Factor X (RFX)-mediated transcriptional rewiring of ciliary genes in animals
- 2010
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 107:29, s. 12969-12974
-
Tidskriftsartikel (refereegranskat)abstract
- Cilia were present in the last eukaryotic common ancestor (LECA) and were retained by most organisms spanning all extant eukaryotic lineages, including organisms in the Unikonta (Amoebozoa, fungi, choanoflagellates, and animals), Archaeplastida, Excavata, Chromalveolata, and Rhizaria. In certain animals, including humans, ciliary gene regulation is mediated by Regulatory Factor X (RFX) transcription factors (TFs). RFX TFs bind X-box promoter motifs and thereby positively regulate >50 ciliary genes. Though RFX-mediated ciliary gene regulation has been studied in several bilaterian animals, little is known about the evolutionary conservation of ciliary gene regulation. Here, we explore the evolutionary relationships between RFX TFs and cilia. By sampling the genome sequences of >120 eukaryotic organisms, we show that RFX TFs are exclusively found in unikont organisms (whether ciliated or not), but are completely absent from the genome sequences of all nonunikont organisms (again, whether ciliated or not). Sampling the promoter sequences of 12 highly conserved ciliary genes from 23 diverse unikont and nonunikont organisms further revealed that phylogenetic footprints of X-box promoter motif sequences are found exclusively in ciliary genes of certain animals. Thus, there is no correlation between cilia/ciliary genes and the presence or absence of RFX TFs and X-box promoter motifs in nonanimal unikont and in nonunikont organisms. These data suggest that RFX TFs originated early in the unikont lineage, distinctly after cilia evolved. The evolutionary model that best explains these observations indicates that the transcriptional rewiring of many ciliary genes by RFX TFs occurred early in the animal lineage.
|
|
