PRECURSOR TO A MINOR SPECIES OF YEAST TRANSFER-RNA SER CONTAINS AN INTERVENING SEQUENCE
PRECURSOR TO A MINOR SPECIES OF YEAST TRANSFER-RNA SER CONTAINS AN INTERVENING SEQUENCE
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DOI：
10.1016/0092-8674(79)90349-0
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发表时间：
1979-01-01
期刊：
影响因子：
64.5
通讯作者：
GUTHRIE, C
中科院分区：
文献类型：
--
作者：
ETCHEVERRY, T;COLBY, D;GUTHRIE, C
酿酒酵母中的某些tRNA（tRNATyr和tRNAPhe）是通过前体分子产生的，这些前体分子在5“和3”末端成熟，但在反密码子附近含有插入序列。除了这些分子外，在非允许温度下，几种其他tRNA的前体在温度敏感突变体（ts 136）中积累。对其中1种物质的分析表明，它是tRNASer次要物质的前体。该前体在两个末端都是成熟的，并且在反密码子3“的高度修饰的A残基附近含有19个核苷酸的间插序列。该序列可以排列在二级结构中，其中反密码子茎通过额外的碱基配对延伸，并且在2个环状区域内含有切除和连接位点。通过分析用RNase T1有限消化的产物，提供了对这种结构的支持。最近报道了分离出一种能解码UCG的tRNASer。该物种在结构上是异质的，并且丰度较低的形式对应于在隐性致死性SUP-RL 1琥珀抑制基因中改变的tRNA。更丰富的形式可能仅限于体内阅读UCA;次要种的突变将导致UCG解码能力的完全丧失，解释了隐性致死解码能力，解释了C-RL 1的隐性致死。积累ts 136的前体专门对应于这种次要物质。图形 **。物种这可能是酵母中唯一含有插入序列的tRNASer基因。
Certain tRNA in Saccharomyces cerevisiae (tRNATyr and tRNAPhe) arise via precursor molecules which are mature at the 5'' and 3'' termini but contain intervening sequences adjacent to the anticodon. In addition to these molecules, precursors to several other tRNA accumulate in a temperature-sensitive mutant (ts136) at the nonpermissive temperature. Analysis of 1 of these species showed that it is a precursor to a minor species of tRNASer. This precursor is mature at both termini and contains an intervening sequence of 19 nucleotides adjacent to the hypermodified A residue 3'' to the anticodon. The sequence can be arranged in a secondary structure in which the anticodon stem is extended by additional base-pairing, and contains the sites of excision and ligation within 2 looped regions. Support for this structure was provided by analysis of the products of limited digestion with RNase T1. Recently the isolation of a minor species of tRNASer which decodes UCG was reported. This species is structurally heterogeneous and the less abundant form corresponds to the tRNA which is altered in the recessive lethal SUP-RL1 amber suppressor. The more abundant form may be restricted to reading UCA in vivo; mutation of the minor species would result in complete loss of UCG-decoding ability, explaining the recessive lethality decoding ability, explaining the recessive lethality of SUP- RL1. The precursor which accumulates the ts136 corresponds exclusively to this minor .**GRAPHIC**. species. This may be the only gene for tRNASer in yeast which contains an intervening sequence.