Carmo-Fonseca M, Tollervey D, Pepperkok R, Barabino S M, Merdes A, Brunner C, Zamore P D, Green M R, Hurt E, Lamond A I
European Molecular Biology Laboratory, Heidelberg, FRG.
EMBO J. 1991 Jan;10(1):195-206. doi: 10.1002/j.1460-2075.1991.tb07936.x.
The organization of the major snRNP particles in mammalian cell nuclei has been analysed by in situ labelling using snRNA-specific antisense probes made of 2'-OMe RNA. U3 snRNA is exclusively detected in the nucleolus while all the spliceosomal snRNAs are found in the nucleoplasm outside of nucleoli. Surprisingly, U2, U4, U5 and U6 snRNAs are predominantly observed in discrete nucleoplasmic foci. U1 snRNA is also present in foci but in addition is detected widely distributed throughout the nucleoplasm. An anti-peptide antibody specific for the non-snRNP splicing factor U2AF reveals it to have a similar distribution to U1 snRNA. Co-localization studies using confocal fluorescence microscopy prove that U2AF is present in the snRNA-containing foci. Antibody staining also shows the foci to contain snRNP-specific proteins and m3G-cap structures. The presence of major components of the nuclear splicing apparatus in foci suggests that these structures may play a role in pre-mRNA processing.
利用由2'-OMe RNA制成的snRNA特异性反义探针进行原位标记，分析了哺乳动物细胞核中主要snRNP颗粒的组织情况。U3 snRNA仅在核仁中被检测到，而所有剪接体snRNA都存在于核仁外的核质中。令人惊讶的是，U2、U4、U5和U6 snRNAs主要出现在离散的核质焦点中。U1 snRNA也存在于这些焦点中，但除此之外，还在整个核质中广泛分布。一种针对非snRNP剪接因子U2AF的抗肽抗体显示其分布与U1 snRNA相似。使用共聚焦荧光显微镜进行的共定位研究证明，U2AF存在于含有snRNA的焦点中。抗体染色还显示这些焦点含有snRNP特异性蛋白和m3G帽结构。核剪接装置的主要成分存在于焦点中，这表明这些结构可能在mRNA前体加工中发挥作用。
