Avi-caspase X Expression in Anterior Regeneration of Aeolosoma viride Is Regulated by the Wnt/β-Catenin Signaling Pathway
| Autor: | Sheridan Ke-wing Fok, 霍其嶸 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 Many invertebrates possess extraordinary regenerative ability to repair their lost tissues or organs. Apoptotic caspases are required during early stage regeneration in Xenopus laevis and many model organisms. Previous study showed that Aelosoma viride could not complete its anterior regeneration when Avi-caspase 6 was knocked down by RNA interference. However, caspase was not the only factor affecting anterior regeneration in A. viride. The canonical wnt/β-Catenin signaling pathway had been prove to be involved in many biological processes such as cell proliferation, cell migration, carcinogenesis, axis formation, and tissue regeneration. Recent studies in Hydra vulgaris also indicated that wnt/β-Catenin signaling might have promoted apoptosis through a caspase-dependent pathway. In A. viride, expression of Avi-wnt-4 elevated in the anterior region during anterior regeneration, and Wnt antagonist, XAV939, showed a significant inhibitory effect during anterior regeneration. In this study, I have identified a novel caspase, Avi-caspase X. Its expression was elevated during anterior regeneration, and was confirmed by both in situ hybridization and quantitative real-time polymerase chain reaction (qRT-PCR). In order to identify the relationship between apoptotic caspase and canonical Wnt signaling pathway, inhibitor of Wnt signaling pathway was applied to observed the change in caspase gene expression. Surprisingly, expression of both Avi-caspase X and Avi-caspase 6 decreased significantly in XAV939 treated group. The Bcl-2 protein family is notable for their regulation of apoptosis. In order to rule out the possibilities of genetic cross talk, two target genes, Bcl-2 associated X protein (apoptosis regulator Bax) and B-cell lymphoma-extra-large (Bcl-xL) from the Bcl-2 family were identified and examined. The gene expression level of Avi-Bax and Avi-Bcl-xL fluctuated during anterior regeneration, and seems to be negatively correlated to each other. Under the treatment with XAV939, the expression level of Avi-Bax decreased along with an increase in gene expression level of Avi-Bcl-xL. Finally, RNA interference (RNAi) of Avi-caspase X was performed by siRNA, further confirmed the relationship between Wnt signaling pathway and apoptotic caspase. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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