碩士 / 國立成功大學 / 生物科技研究所碩博士班 / 90 / Immunoglobulin produced by B lymphocytes is a major protein involved in the humoral immune response. The variable region of Ig gene is assembled during B lymphocyte development by the recombination of multiple V, D, J segments. This V(D)J rearrangement process generates a vast array of antigen receptors and is strictly mediated by RAG recombinase, encoded by recombination activation gene-1 and -2. Because rag-1 gene, especially in the enzyme-activating core region, is highly conserved among species from teleost to mammals and is critical to the differentiation of pre-B cells, its expression within an associated primary lymphoid organ can serve as an ideal developmental marker to determine the location of immune organs. Besides, in order to study the maturity level of immune system with respect to time during cobia ontogeny, the expression patterns of rag-1 and Ig gene at different cobia growth stages (from embryo to fry stages) were examined.
In addition to the use of β-actin gene as an internal control, partial rag-1 and Ig genes form cobia, Rachycentron canadum, each with an amplified size 637bp and 225bp respectively, were successfully clones. When compared with other previously reported rag-1 or Ig sequences of different fish species, the predicted rag-1 and Ig amino acid sequences of cobia displayed a minimum of 87% and 33% similarity. Tissue-specific expression of rag-1 was examined both by northern blotting and RT-PCR assay. The highest level of rag-1 expression was observed in the thymus, and a weaker expression was observed in spleen and kidney. This result indicated that thymus might be the most important immune organ compared to spleen and kidney.The expression patterns of rag-1 and Ig genes were both detected on the 7th day after hatching by RT-PCR assay. This suggested that cobia at this stage might possess mature immunity and is able to produce immunoglobulin.
| Identifer | oai:union.ndltd.org:TW/090NCKU5111005 |
| Date | January 2002 |
| Creators | Chun-Chieh Wang, 王俊傑 |
| Contributors | 楊惠郎 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 78 |
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