Reddy R, Spector D, Henning D, Liu M H, Busch H
J Biol Chem. 1983 Nov 25;258(22):13965-9.
The dinoflagellates are a group of diverse eukaryotic algae possessing a number of unique cellular properties. Evidence is presented for the presence of six capped small nuclear RNAs in these dinoflagellates. By several criteria such as the (a) presence of trimethylguanosine cap structure in U1 to U5 RNAs, (b) sequence homology between rat and dinoflagellate U2, U5 and U6 RNAs, (c) presence of other post-transcriptional modifications such as sugar and base modifications, and (d) association of Sm antigen with five of these six RNAs, the six RNAs of dinoflagellates appear to be similar to the well characterized U1 to U6 RNAs found in higher eukaryotes. This is the first demonstration of antigenic small nuclear RNA-containing particles in any unicellular organism. These results suggest that the U1 to U6 RNAs and the associated Sm antigen evolved at a very early stage of eukaryotic evolution. With respect to U small nuclear RNAs and their associated proteins, the dinoflagellates appear to exhibit eukaryotic characteristics.
甲藻是一类具有多种独特细胞特性的多样真核藻类。有证据表明这些甲藻中存在六种带帽小核RNA。通过诸如（a）U1至U5 RNA中存在三甲基鸟苷帽结构、（b）大鼠与甲藻U2、U5和U6 RNA之间的序列同源性、（c）存在其他转录后修饰如糖基和碱基修饰，以及（d）Sm抗原与这六种RNA中的五种相关联等多个标准，甲藻的这六种RNA似乎类似于在高等真核生物中已充分表征的U1至U6 RNA。这是在任何单细胞生物中首次证明含抗原性小核RNA的颗粒。这些结果表明U1至U6 RNA以及相关的Sm抗原在真核生物进化的非常早期阶段就已进化。关于U小核RNA及其相关蛋白方面，甲藻似乎表现出真核生物特征。
