证明7纳米核糖核蛋白纤维是前体信使核糖核蛋白颗粒中的基本结构元件。

Demonstration of a 7-nm RNP fiber as the basic structural element in a premessenger RNP particle.

作者信息

Lönnroth A, Alexciev K, Mehlin H, Wurtz T, Skoglund U, Daneholt B

机构信息

Department of Molecular Genetics, Medical Nobel Institute, Karolinska Institutet, Stockholm, Sweden.

出版信息

Exp Cell Res. 1992 Apr;199(2):292-6. doi: 10.1016/0014-4827(92)90437-d.

DOI:10.1016/0014-4827(92)90437-d

PMID:1544370

Abstract

Balbiani ring granules in Chironomus salivary glands represent premessenger ribonucleoprotein (RNP) particles, each containing a 35- to 40-kb message for a secretory polypeptide. Their gross structure can be described as an RNP ribbon bent into a toroid. We now demonstrate that an unfolded, thin RNP fiber is observed after low salt treatment of isolated Balbiani ring granules. Moreover, the thin RNP fiber, 7 nm in diameter, can be revealed as the main structural element in Balbiani ring granules studied in situ in 3-D with electron microscope tomography. It is proposed that the thin RNP fiber consists of a premessenger RNA molecule coiled around a filamentous core of polymeric proteins, which has functional implications for processes such as assembly of RNP, intranuclear degradation of RNA, and delivery of RNA through the nuclear pores.

摘要

摇蚊唾液腺中的巴尔比亚尼环颗粒代表前信使核糖核蛋白（RNP）颗粒，每个颗粒都包含一个用于分泌多肽的35至40千碱基的信息。它们的总体结构可描述为一条弯曲成环形的RNP带。我们现在证明，对分离出的巴尔比亚尼环颗粒进行低盐处理后，可以观察到未折叠的细RNP纤维。此外，直径为7纳米的细RNP纤维可以通过电子显微镜断层扫描三维原位研究，揭示为巴尔比亚尼环颗粒中的主要结构元件。有人提出，细RNP纤维由缠绕在聚合蛋白丝状核心周围的前信使RNA分子组成，这对RNP组装、RNA的核内降解以及RNA通过核孔的转运等过程具有功能意义。