碩士 / 國立臺灣大學 / 生化科學研究所 / 100 / In eukaryotes, Four-and-a-half LIM domains (FHL) protein family is highly conserved. Structurally, the FHL proteins are composed of four closely connected LIM domains arranged in tandem, which are cysteine-rich double zinc finger motifs; and an N-terminal half LIM domain, which has one zinc finger motif. The LIM domain is known for mediating protein-protein interaction. Based on its protein-protein interaction properties, FHL protein family can interact with many proteins. Such like structural proteins, kinases and many transcription factors. The presence of multiple LIM domains, suggests that FHL protein family may involve in many cellular mechanisms. Including cellular survival, transcription regulation and signal transduction. The tissue-specific expression pattern of FHL protein family is mainly at cardiac muscular and skeletal muscle. Therefore the FHL protein family plays an important role in muscle and cardiovascular differentiation and the function maintenance.
In our study, by alignment of the FHL protein sequences in human, mouse and zebrafish and the results of whole mount in situ hybridization assay. Our results shows that FHL protein family are highly conserved and mainly expressed in heart and some part of skeletal muscle, suggest the importance of FHL protein family in the cardiomyocyte. We further analysed the role of FHL protein in the heart development by overexpressed several FHL proteins fused GFP including FHL1, FHL2 and FHL5, in zebrafish heart by a cardiac-specific promoter; cmlc2. The results turned out that a certain number of the FHL-GFP-positive offspring of transgenic line had arrhythmia. This indicates that FHL protein plays a role in regulation of heart rhythm. Next, we intend to rescue the phenotype of arrhythmia. Transgenic zebrafish which overexpressed different combination of FHL proteins, were treated with isoprenaline, a cardiac stimulant. Different FHL transgenic zebrafish embryos of 5-6dpf were immersed with different concentration of isoprenaline and heart beat were recorded daily. Our results demonstrated that isoprenaline could significantly rescue arrhythmia phenotype. However, long-term treatment had resulted in dramatic drop of survival rate and the recurring of irregular heart beat of FHL overexpressed transgenic line. Therefore further studies may be required to decipher the mechanism in the future. Taken together, our studies provide more understandings about the function of FHL protein in heart, the role in the cardiac disease, and established a zebrafish arrhythmia model for cardiovascular drug selection.
| Identifer | oai:union.ndltd.org:TW/100NTU05103111 |
| Date | January 2012 |
| Creators | Chih-Ting Shih, 施繼庭 |
| Contributors | Chang-Jen Huang, 黃銓珍 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 79 |
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