Scott William G, Martick Monika, Chi Young-In
Center for the Molecular Biology of RNA, Sinsheimer Laboratory, University of California at Santa Cruz, Santa Cruz, CA, USA.
Biochim Biophys Acta. 2009 Sep-Oct;1789(9-10):634-41. doi: 10.1016/j.bbagrm.2009.09.006. Epub 2009 Sep 23.
Since their discovery in the 1980s, it has gradually become apparent that there are several functional classes of naturally occurring ribozymes. These include ribozymes that mediate RNA splicing (the Group I and Group II introns, and possibly the RNA components of the spliceosome), RNA processing ribozymes (RNase P, which cleaves precursor tRNAs and other structural RNA precursors), the peptidyl transferase center of the ribosome, and small, self-cleaving genomic ribozymes (including the hammerhead, hairpin, HDV and VS ribozymes). The most recently discovered functional class of ribozymes include those that are embedded in the untranslated regions of mature mRNAs that regulate the gene's translational expression. These include the prokaryotic glmS ribozyme, a bacterial riboswitch, and a variant of the hammerhead ribozyme, which has been found embedded in mammalian mRNAs. With the discovery of a mammalian riboswitch ribozyme, the question of how an embedded hammerhead ribozyme's switching mechanism works becomes a compelling question. Recent structural results suggest several possibilities.
自20世纪80年代被发现以来，逐渐显露出天然存在的核酶有几个功能类别。这些包括介导RNA剪接的核酶（I类和II类内含子，可能还有剪接体的RNA组分）、RNA加工核酶（RNase P，其切割前体tRNA和其他结构RNA前体）、核糖体的肽基转移酶中心，以及小型、自我切割的基因组核酶（包括锤头状、发夹状、丁型肝炎病毒和VS核酶）。最近发现的核酶功能类别包括那些嵌入成熟mRNA非翻译区以调节基因翻译表达的核酶。这些包括原核生物的glmS核酶、一种细菌核糖开关，以及已发现嵌入哺乳动物mRNA中的锤头状核酶变体。随着哺乳动物核糖开关核酶的发现，嵌入的锤头状核酶的开关机制如何起作用的问题成为一个引人关注的问题。最近的结构研究结果提出了几种可能性。
