Potter S, Durovic P, Dennis P P
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada.
Science. 1995 May 19;268(5213):1056-60. doi: 10.1126/science.7538698.
An RNA-containing endonuclease that catalyzes the excision and maturation of the 16S ribosomal RNA (rRNA) from the rRNA primary transcript (pre-rRNA) in the hyperthermophilic archaeon Sulfolobus acidocaldarius has been characterized. The ribonucleoprotein was inactivated by micrococcal nuclease treatment and inactivation was reversed by reconstitution with bulk RNA. A 159-nucleotide RNA with sequence and structural similarity to U3 small nucleolar RNAs of eukaryotes copurified with the endonuclease activity. Oligonucleotide-targeted ribonuclease H inactivation of the U3-like RNA component also abolished processing activity. A motif within the U3 homolog is complementary to the region around the three cleavage sites in the pre-RNA substrate. Thus, U3-mediated processing of pre-rRNA is not specific to eukaryotes; its origin predates the divergence of archaea and eukaryotes.
已对一种含RNA的内切核酸酶进行了表征，该酶催化嗜热古菌嗜酸热硫化叶菌中16S核糖体RNA（rRNA）从rRNA初级转录本（前体rRNA）的切除和成熟。核糖核蛋白经微球菌核酸酶处理后失活，通过与大量RNA重组可使失活逆转。一种与真核生物U3小核仁RNA具有序列和结构相似性的159个核苷酸的RNA与内切核酸酶活性共同纯化。针对U3样RNA成分的寡核苷酸靶向核糖核酸酶H失活也消除了加工活性。U3同源物中的一个基序与前体RNA底物中三个切割位点周围的区域互补。因此，U3介导的前体rRNA加工并非真核生物所特有；其起源早于古菌和真核生物的分化。
