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The structure of ribosomal protein genes and the control mechanisms of their expression

核糖体蛋白基因的结构及其表达控制机制

基本信息

批准号：
61570117
负责人：
TANAKA Tatsuo
金额：
$ 1.54万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

The biogenesis of eucaryotic ribosomes requires an equimolar accumulation of four RNAs and over 70 different ribosomal protein molecules. This stoichiometry is maintained over a wide range of physiological conditions by coordinate regulation. We intended to study the structure of the genes for individual ribosomal proteins to investigate the control mechanisms.Clones containing cDNA inserts complementary to the mRNAs encoding ribosomal proteins S11, S17, S26, L5, L7a, L27, L30, L31, L35a, and L37a were isolated by hybrid-selected translation from the cDNA library made for 8-9 s poly(A)-RNA from regenerating rat liver. The nucleotide sequences of these cDNA were determined. The structures of these proteins were infered from the nucleotide sequences to confirm the identity of these clones.Using the recombinat DNAs, we found that the relative abundance of the mRNAs of these proteins increased after partial hepatectomy. Their maximal level was about twice that of normal rat liver, and was achieved 12-18 h after the operation. The abundance decreased near to the normal level after 48 h.The rat ribosomal protein genes comprise multigene families which contain 15-20 memberes as shown by the Southern blot anaylyses using the cDNAs as probes. We isolated many independent clones of S11,L27,and L35a from a rat genomic library. Analysis of the restiction sites showed that all of them lacked the intervening seguences. Thermal stability of the hybrid molecules beween these genes and the cDNAs indicated that the nucleotide sequences of these genes had various similarities to the the sequences of the cDNAs. These genes lacked the intervening sequence, they contained (A)-rich tracts, and they were flanked by direct repeats. Thus, the ribosomal protein gene families were proven to comprise mostly processed pseudogenes.

真核核糖体的生物发生需要四种 RNA 和 70 多种不同核糖体蛋白质分子的等摩尔积累。通过协调调节，这种化学计量在很宽的生理条件下得以维持。我们打算研究单个核糖体蛋白的基因结构，以研究控制机制。通过杂交选择翻译从 8-9 s 的 cDNA 文库中分离出含有与编码核糖体蛋白 S11、S17、S26、L5、L7a、L27、L30、L31、L35a 和 L37a 的 mRNA 互补的 cDNA 插入片段的克隆。来自再生大鼠肝脏的聚 (A)-RNA。确定了这些cDNA的核苷酸序列。从核苷酸序列推断这些蛋白质的结构，以确认这些克隆的身份。使用重组DNA，我们发现这些蛋白质的mRNA相对丰度在部分肝切除术后增加。它们的最高水平约为正常大鼠肝脏的两倍，并在术后12-18小时达到。 48小时后丰度下降至接近正常水平。使用cDNA作为探针的Southern印迹分析表明，大鼠核糖体蛋白基因包含多基因家族，其中包含15-20个成员。我们从大鼠基因组文库中分离出许多独立的 S11、L27 和 L35a 克隆。对限制位点的分析表明，所有限制位点都缺乏插入序列。这些基因和cDNA之间的杂合分子的热稳定性表明这些基因的核苷酸序列与cDNA的序列具有多种相似性。这些基因缺乏插入序列，它们含有富含 (A) 的区域，并且两侧是同向重复序列。因此，核糖体蛋白基因家族被证明主要包含加工过的假基因。