碩士 / 國立臺灣大學 / 動物學研究所 / 88 / Translational control is very important for oogenesis. Expression of many messages in oocytes is temporally regulated. These messages may not be translated immediately. Instead, they are utilized to produce proteins that participate in the formation of tissues and organs in a particular phase of embryogenesis.
Our data indicates that a large amount of the mRNA of chorion components, including ZP2 and ZP3, are transcribed during early stage of oogenesis, yet synthesis of ZP2 and ZP3 proteins are delayed until the late stage of oogenesis. Therefore, the transcription and translation of ZP2 and ZP3 are asynchronous. Such a phenomena is also found in many other organisms. Therefore, we intended to investigate the possible mechanisms that may regulate the protein synthesis during oogenesis.
In order to realize the protein synthesis rate in oocyte of different developmental stages, the polysome profile of previtellogenic oocytes and fully-grown oocytes was investigated. The content of polysome of fully-grown oocytes is far exceeding that of previtellogenic oocytes by about 150 folds, suggesting that the fully-grown oocytes have a much higher protein synthesis rate than that of the previtellogenic oocytes. In order to study whether such a lower protein synthesis rate was also happened to the chorion components, the amount of ZP2 mRNA involved in translation in previtellogenic oocytes and fully-grown oocytes was compared. It is found that the amount of ZP2 mRNA present in polysome fraction of fully-grown oocytes is 5 folds higher than that present in previtellogenic oocytes.
Initiation factors of translation are key regulators of protein synthesis. For the sake to understand whether these factors are actually involved in regulation of protein synthesis during oogenesis in carp, I clone three initiation factors of translation, eIF2α, eIF2β, and eIF4E. The eIF2αis 1279 bps in length that encodes a protein of 307 amino acids. The partial sequence of eIF2βand eIF4E were also cloned. All these factors are homologous to the ones of other organisms. Northern blotting reveals that eIF4E expresses more in the fully-grown oocytes than in the previtellogenic oocytes.
In the present study, the recombinant proteins of eIF2α, eIF2β, and eIF4E were expressed and used to induce antibodies. Western blotting data indicated that only the antiserum of eIF2αcould recognize a specific protein of expected molecular weight from the crude extract of previtellogenic oocytes and liver but fail to do so on the crude extract of fully-grown oocytes. Therefore, I can not obtain any information from Western blots as whether eIF2α, eIF2β, and eIF4E may regulate the protein synthesis in carp oocytes.
| Identifer | oai:union.ndltd.org:TW/088NTU00312016 |
| Date | January 2000 |
| Creators | Yu-Ming Yang, 楊育明 |
| Contributors | Fore-Lien Huang, Yea-Sha Chang, 黃火鍊, 張月霞 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 65 |
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