A tertiary interaction detected in a human U2-U6 snRNA complex assembled in vitro resembles a genetically proven interaction in yeast.
A tertiary interaction detected in a human U2-U6 snRNA complex assembled in vitro resembles a genetically proven interaction in yeast.
复制标题
在体外组装的人类 U2-U6 snRNA 复合物中检测到的三级相互作用类似于酵母中经基因证明的相互作用。
DOI：
10.1017/s1355838200992197
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Manley,JL
中科院分区：
文献类型：
--
作者：
Valadkhan,S;Manley,JL
U2 and U6 small nuclear RNAs are thought to play critical roles in pre-mRNA splicing catalysis. Genetic evidence suggests they form an extensively base-paired structure within the spliceosome that is required for catalysis. Especially in light of significant similarities with group II self-splicing introns, we wished to investigate whether the purified RNAs might by themselves be able to form a complex similar to that which appears to exist in the spliceosome. To this end, we synthesized and purified large segments of human U2 and U6 snRNAs. Upon annealing, the two RNAs efficiently formed a stable and apparently extensively base-paired (Tm = 50–60 °C in the presence of 20 mM Mg2+) complex. To investigate possible tertiary interactions, we subjected the annealed complex to UV irradiation, and two crosslinked species were identified and characterized. The major one links the second G in the highly conserved and critical ACAGAGA sequence in U6 with an A in U2 just 5′ to U2-U6 helix Ia and opposite the invariant AGC in U6. Remarkably, this crosslink indicates a tertiary interaction essentially identical to one detected previously by genetic covariation in yeast. Together our results suggest that purified U2 and U6 snRNAs can anneal and fold to form a structure resembling that likely to exist in the catalytically active spliceosome.
