DIFFERENTIAL BINDING OF OOCYTE-TYPE AND SOMATIC-TYPE 5S RIBOSOMAL-RNA TO TFIIIA AND RIBOSOMAL-PROTEIN L5 IN XENOPUS OOCYTES - SPECIALIZATION FOR STORAGE VERSUS MOBILIZATION
DIFFERENTIAL BINDING OF OOCYTE-TYPE AND SOMATIC-TYPE 5S RIBOSOMAL-RNA TO TFIIIA AND RIBOSOMAL-PROTEIN L5 IN XENOPUS OOCYTES - SPECIALIZATION FOR STORAGE VERSUS MOBILIZATION
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DOI：
10.1006/dbio.1995.1080
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发表时间：
1995-04-01
影响因子：
2.7
通讯作者：
NEVILLE, LA
中科院分区：
文献类型：
--
作者：
ALLISON, LA;NORTH, MT;NEVILLE, LA
我们研究了非洲爪哇卵子发生过程中5S核糖体RNA(RRNA)从细胞质中储存到核糖体中的途径。核糖核蛋白颗粒(RNP)组装分析表明，将5S rRNA显微注射到II、III、IV期卵母细胞或V-VI期卵母细胞的细胞质中后，卵母细胞型和体细胞型5S rRNA的行为明显不同。显微注射的卵细胞型5S rRNA主要与5S rRNA基因特异性转录因子IIIA(TFIIIA)相互作用，形成75RNPs。相比之下，显微注射的体细胞型5S rRNA主要与核糖体蛋白L5相互作用形成5S RNPs，这是核糖体组装的前体。此外，更多的体细胞类型的5S rRNA聚集在细胞核中，并组装成60S核糖体亚基。因此，核苷酸序列的微小差异导致5S rRNA与TFIIIA和L5的不同结合，专门化的卵母细胞类型用于储存在卵母细胞胞浆中，而体细胞类型用于快速动员和核糖体组装。当卵细胞型和体细胞型5S rRNA分子比其他核糖体成分更多地注入V-VI期卵母细胞的核内时，这两种类型的RNA的核质分布相似，但保持了独特的蛋白质组合。相比之下，从显微注射克隆基因中原位逐渐合成的卵细胞型和体细胞型5S rRNA的行为相似，这表明新生RNA迅速并直接招募到核糖体，从而绕过了在核糖体组装之前进入细胞质的过程。(C)1995年学术出版社。
We studied the pathway of 5S ribosomal RNA (rRNA) during oogenesis in Xenopus from its storage in the cytoplasm to incorporation into ribosomes in the nucleus. Ribonucleoprotein particle (RNP) assembly assays reveal striking differences in the behavior of oocyte-type and somatic-type 5S rRNA after microinjection into stage II, III, or IV oocytes or into the cytoplasm of stage V-VI oocytes. Microinjected oocyte-type 5S rRNA predominantly interacts with the 5S rRNA gene-specific transcription factor IIIA (TFIIIA) to form storage 75 RNPs. In contrast, microinjected somatic-type 5S rRNA predominantly interacts with ribosomal protein L5 to form 5S RNPs, which are precursors to ribosome assembly. In addition, a greater amount of somatic-type 5S rRNA accumulates in the nucleus and is assembled into 60S ribosomal subunits. Thus, a slight difference in nucleotide sequence results in differential binding of 5S rRNA to TFIIIA and L5, specializing oocyte-type for storage in the oocyte cytoplasm and somatic-type for rapid mobilization and ribosome assembly. When oocyte-type and somatic-type 5S rRNA molecules were microinjected into the nucleus of stage V-VI oocytes in excess of other ribosomal components, the nucleocytoplasmic distribution of both types of RNA was similar, but the distinctive protein associations were maintained. In contrast, the behavior of oocyte-type and somatic-type 5S rRNA gradually synthesized in situ from microinjected cloned genes was similar, suggesting that nascent RNA is rapidly and directly recruited into ribosomes, thus bypassing an excursion into the cytoplasm prior to ribosome assembly. (C) 1995 Academic Press, Inc.