Antal M, Mougin A, Kis M, Boros E, Steger G, Jakab G, Solymosy F, Branlant C
Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, H-6701 Szeged, PO Box 521, Hungary.
Nucleic Acids Res. 2000 Aug 1;28(15):2959-68. doi: 10.1093/nar/28.15.2959.
A U3 snoRNA gene isolated from a Chlamydomonas reinhardtii (CRE:) genomic library contains putative pol III-specific transcription signals similar to those of RNA polymerase III-specific small nuclear (sn)RNA genes of higher plants. The 222 nt long CRE: U3 snoRNA was immunoprecipitated by anti-gamma-mpppN antisera, but not by anti-m(2,2,7)G antibodies, supporting the notion that it is a RNA polymerase III transcript. Tagged CRE: U3 snoRNA gene constructs were expressed in CRE: cells. Results of chemical and enzymatic structure probing of CRE: U3 snoRNA in solution and of DMS modification of CRE: U3 snoRNA under in vivo conditions revealed that the two-hairpin structure of the 5'-domain that is found in solution is no longer detected under in vivo conditions. The observed differences can be explained by the formation of several base pair interactions with the 18S and 5'-ETS parts of the pre-rRNA. A model that involves five intermolecular helices is proposed.
从莱茵衣藻（CRE:）基因组文库中分离出的一个U3小核仁RNA基因，含有与高等植物RNA聚合酶III特异性小核（sn）RNA基因相似的推定的聚合酶III特异性转录信号。长度为222个核苷酸的CRE: U3小核仁RNA可被抗γ-mpppN抗血清免疫沉淀，但不能被抗m(2,2,7)G抗体免疫沉淀，这支持了它是RNA聚合酶III转录本的观点。带有标签的CRE: U3小核仁RNA基因构建体在CRE:细胞中表达。对溶液中的CRE: U3小核仁RNA进行化学和酶促结构探测以及在体内条件下对CRE: U3小核仁RNA进行二甲基亚砜（DMS）修饰的结果显示，在溶液中发现的5'-结构域的双发夹结构在体内条件下不再被检测到。观察到的差异可以通过与前体核糖体RNA的18S和5'-外部转录间隔区（5'-ETS）部分形成几个碱基对相互作用来解释。提出了一个涉及五个分子间螺旋的模型。
