Demonstration of a 7-nm RNP fiber as the basic structural element in a premessenger RNP particle |
| |
Authors: | A Lnnroth K Alexciev H Mehlin T Wurtz U Skoglund B Daneholt |
| |
Institution: | Department of Molecular Genetics, Medical Nobel Institute, Karolinska Institutet, Stockholm, Sweden. |
| |
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. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|