一种从U6小核仁RNA变体中筛选出的核酶可促进2',5'-分支的形成。
A ribozyme selected from variants of U6 snRNA promotes 2',5'-branch formation.
作者信息
Tuschl T, Sharp P A, Bartel D P
机构信息
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
出版信息
RNA. 2001 Jan;7(1):29-43. doi: 10.1017/s1355838201001510.
In vitro selection was used to sample SnRNA-related sequences for ribozyme activities, and several 2',5'-branch-forming ribozymes were isolated. One such ribozyme is highly dependent upon an 11-nt motif that contains a conserved U6 snRNA sequence (ACAGAGA-box) known to be important for pre-mRNA splicing. The ribozyme reaction is similar to the first step of splicing in that an internal 2'-hydroxyl of an unpaired adenosine attacks at the 5'-phosphate of a guanosine. It differs in that the leaving group is diphosphate rather than a 5' exon. The finding that lariat formation can be accomplished by a small RNA with sequences related to U6 snRNA indicates that the RNA available in the spliceosome may be involved in RNA-catalyzed branch formation.
利用体外筛选来获取具有核酶活性的小核仁RNA（snRNA）相关序列，并分离出了几种能形成2'，5'-分支的核酶。其中一种核酶高度依赖于一个11个核苷酸的基序，该基序包含一个保守的U6 snRNA序列（ACAGAGA框），已知该序列对前体mRNA剪接很重要。核酶反应与剪接的第一步类似，即未配对腺苷的内部2'-羟基攻击鸟苷的5'-磷酸。不同之处在于离去基团是二磷酸而不是5'外显子。与U6 snRNA相关序列的小RNA能够完成套索状结构的形成，这一发现表明剪接体中可用的RNA可能参与了RNA催化的分支形成。
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