Sarkar M, Vinayak M
National Institute of Health, Tokyo, Japan.
Mol Biol Rep. 1998 Mar;25(2):127-33. doi: 10.1023/a:1006836415897.
The present study is a comparison of tRNA conformation from ovary of Heteropneustes fossilis in its active phase of reproduction (when it is highly engaged in protein synthesis i.e. previtellogenic phase) with inactive phase (when tRNA is mainly stored in mature ovary i.e. spawning phase). Transfer RNA of active phase is shown to be compact, flexible and susceptible towards nuclease. Compact tRNA structure is evidenced by higher hyperchromicity and presence of relatively less Gm modifications thereby allowing adequate hydrogen bonding between D loop and T loop. Higher sensitivity of tRNA towards Mg++ reflects its higher flexibility towards internal environment. This structure of tRNA may be required for active protein synthesis. On the other hand tRNA of inactive phase is shown to be relaxed but resistant towards nuclease which may be favoured for storage in mature ova of a teleost as maternal carry over.
本研究比较了印度胡鲶卵巢在繁殖活跃期（即高度参与蛋白质合成时，也就是卵黄生成前期）和非活跃期（即tRNA主要储存在成熟卵巢时，也就是产卵期）的tRNA构象。结果显示，活跃期的转移RNA结构紧密、灵活且易被核酸酶作用。较高的增色效应以及相对较少的Gm修饰证明了tRNA结构紧密，从而使得D环和T环之间能够形成足够的氢键。tRNA对Mg++的较高敏感性反映了其对内部环境具有较高的灵活性。这种tRNA结构可能是活跃蛋白质合成所必需的。另一方面，非活跃期的tRNA结构较为松散，但对核酸酶具有抗性，这可能有利于作为母本遗传物质储存在硬骨鱼的成熟卵子中。
