Fang G, Cech T R
Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215, USA.
J Cell Biol. 1995 Jul;130(2):243-53. doi: 10.1083/jcb.130.2.243.
The intranuclear distribution of telomere DNA-binding protein and telomerase RNA in hypotrichous ciliates was revealed by indirect fluorescent antibody staining and in situ hybridization. The Oxytricha telomere protein colocalized with DNA, both being dispersed throughout the macronucleus except for numerous spherical foci that contained neither DNA nor the protein. Surprisingly, the telomerase RNA was concentrated in these foci; therefore, much of telomerase does not colocalize with telomeres. These foci persist through the cell cycle. They may represent sites of assembly, transport or stockpiling of telomerase and other ribonucleoproteins. During S phase, the macronuclear DNA replication machinery is organized into a disc-shaped structure called the replication band. Telomerase RNA is enriched in the replication band as judged by fluorescence intensity. We conclude that the localization of a subfraction of telomerase is coordinated with semiconservative DNA replication.
通过间接荧光抗体染色和原位杂交揭示了端粒DNA结合蛋白和端粒酶RNA在纤毛虫中的核内分布。嗜氧菌的端粒蛋白与DNA共定位，二者均分散于整个大核中，但存在许多既不含DNA也不含该蛋白的球形焦点。令人惊讶的是，端粒酶RNA集中在这些焦点中；因此，大部分端粒酶并不与端粒共定位。这些焦点在细胞周期中持续存在。它们可能代表端粒酶和其他核糖核蛋白的组装、运输或储存位点。在S期，大核DNA复制机制被组织成一种称为复制带的盘状结构。根据荧光强度判断，端粒酶RNA在复制带中富集。我们得出结论，端粒酶亚组分的定位与半保留DNA复制是协调的。
