TELOMERASE RNAS OF DIFFERENT CILIATES HAVE A COMMON SECONDARY STRUCTURE AND A PERMUTED TEMPLATE
TELOMERASE RNAS OF DIFFERENT CILIATES HAVE A COMMON SECONDARY STRUCTURE AND A PERMUTED TEMPLATE
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DOI：
10.1101/gad.8.16.1984
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发表时间：
1994-08-15
影响因子：
10.5
通讯作者：
CECH, TR
中科院分区：
文献类型：
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作者：
LINGNER, J;HENDRICK, LL;CECH, TR
端粒酶由蛋白质和RNA组成。RNA作为端粒DNA合成的模板，也可能对酶结构或催化作用很重要。我们已经使用的启动子和模板区域中的保守序列元件的存在下，通过PCR扩增端粒酶RNA基因从六个不同的hypotrichous纤毛虫：Oxytricha新星，Oxytricha trifallax，Stylonychia myeloma，Stylonychia lemeloma，Euplotes aediculatus，和Euplotes eurystomus。RNaseH酶切O.通过使用互补寡核苷酸在提取物中检测nova RNA导致端粒酶活性丧失，支持鉴定。一级序列和生化实验表明尖毛藻和柱甲藻的模板相对于B的模板是循环排列的。aediculatus前两者在一个引物延伸循环中，在停顿位点的基础上增加了G（3）T（4），而E. aediculatus加G（3）T（4）G.在这些遗传学上远距离的端粒酶RNA之间保守的模板外的唯一一级序列元件是序列5 '-（C）UGUCA-3'，其在模板区域之前正好两个碱基。我们提出了一个共同的二级结构模型，是基于核苷酸的协变，一个模型，类似于先前提出的四膜虫端粒酶RNA。
Telomerase is composed of protein and RNA. The RNA serves as a template for telomere DNA synthesis and may also be important for enzyme structure or catalysis. We have used the presence of conserved sequence elements in the promoter and template regions to amplify by PCR the telomerase RNA genes from six different hypotrichous ciliates: Oxytricha nova, Oxytricha trifallax, Stylonychia mytilis, Stylonychia lemnae, Euplotes aediculatus, and Euplotes eurystomus. RNaseH cleavage of the O. nova RNA in extracts by use of a complementary oligonucleotide leads to loss of telomerase activity, supporting the identification. Primary sequence and biochemical experiments suggest that the templates of Oxytricha and Stylonychia are circularly permuted relative to that of B. aediculatus. On the basis of the pause sites, the former two add G(3)T(4) during a single primer elongation cycle, whereas E. aediculatus adds G(3)T(4)G. The only primary sequence element outside the template that is conserved between these phylogenetically distant telomerase RNAs is the sequence 5'-(C)UGUCA-3', which precedes the template regions by exactly two bases. We propose a common secondary structure model that is based on nucleotide covariations, a model which resembles that proposed previously for tetrahymenine telomerase RNAs.