Laboratory of RNA Archeology, Instituto de Parasitología y Biomedicina 'López-Neyra', CSIC, Armilla, 18100 Granada, Spain.
Nucleic Acids Res. 2012 Feb;40(4):1748-66. doi: 10.1093/nar/gkr822. Epub 2011 Oct 11.
A novel UV-C-light-induced ribozyme activity was discovered within the highly structured 5'-genomic regions of both Hepatitis C Virus (HCV) and the related Classic Swine Fever Virus (CSFV). Cleavage is mediated by exposure to UV-C light but not by exogenous oxygen radicals. It is also very selective, occurring at base positions HCV C(79) and CSFV A(45) in some molecules and at the immediately adjacent 5'-positions HCV U(78) and CSFV U(44) in others. Among other reaction products, the majority of biochemically active products detected contained 3'-phosphate and 5'-phosphate-end groups at the newly generated termini, along with a much lower amount of 3'-hydroxyl end group. While preservation of an E-loop RNA structure in the vicinity of the cleavage site was a requisite for HCV RNA self-cleavage, this was not the case for CSFV RNA. The short size of the reactive domains (~33 nt), which are compatible with primitive RNA motifs, and the lack of sequence homology, indicate that as-yet unidentified UV-activated ribozymes are likely to be found throughout structured RNAs, thereby providing clues to whether early RNA self-cleavage events were mediated by photosensitive RNA structures.
一种新型的紫外光诱导核酶活性在丙型肝炎病毒（HCV）和相关经典猪瘟病毒（CSFV）的高度结构化 5'-基因组区域内被发现。这种切割是由暴露在紫外光下介导的，而不是由外源性氧自由基介导的。它也非常具有选择性，在一些分子中发生在 HCV C(79)和 CSFV A(45)的碱基位置，而在其他分子中则发生在 HCV U(78)和 CSFV U(44)的紧邻 5'-位置。在其他反应产物中，检测到的大多数具有生物活性的产物在新生成的末端处含有 3'-磷酸和 5'-磷酸末端基团，以及少量的 3'-羟基末端基团。虽然在切割位点附近保留 E-环 RNA 结构是 HCV RNA 自我切割的必要条件，但 CSFV RNA 并非如此。反应区域的短尺寸（~33nt）与原始 RNA 基序兼容，并且缺乏序列同源性，表明可能在整个结构 RNA 中发现了尚未识别的紫外激活核酶，从而为早期 RNA 自我切割事件是否由光敏 RNA 结构介导提供了线索。
