微核仁是富含剪接因子SC35的核内小体

Mininucleolus: An Intranuclear Body Enriched with the Splicing Factor SC35 

许多植物细胞核中存在一些较小的球形或卵圆形的结构，不同作者分别将其称为球体（ｓｐｈｅｒｕｌｅｓ）［１］、核体（ｋａｒｙｏｓｏｍｅ）［２］、核仁附着小体（ｎｕｃｌｅｏｌｕｓａｓｏｃｉａｔｅｄｂｏｄｉｅｓ）［３］、螺旋小体（ｃｏｉｌｅｄｂｏｄｉｅｓ）［４...

The mininucleolus (MN) is a distinct intranuclear body often observed in cells of higher plants. Previous studies indicated MN as a non chromatin structure composed of RNA and proteins, and suggested that it may be involved in the transportation and storage of ribosomal RNA. However, its characteristic protein component and functional significance remain to be clarified. The authors investigated the characteristic protein component of MNs in the nuclei of the meristematic cells of root in Vicia faba L. approaching with an anti SC35 monoclonal antibody and immunoelectron microscopic observation. A large number of gold particles were observed over the MNs of the specimens labelled with the antibody and protein A gold, while only a few gold particles were found in the MNs of the control specimens in which labelling of the antibody was omitted. The density of gold particles in MNs of the labelled specimens (300/μm 2) was much higher than that of the control specimens (3.76 /μm 2), demonstrating that SC35 is a constituent of the MN. The identification of the MN highly enriched with the splicing factor will help us understanding the function of this structure.