TRANSCRIPTIONAL AND TRANSLATIONAL INITIATION SITES OF IS50 CONTROL OF TRANSPOSASE AND INHIBITOR EXPRESSION
TRANSCRIPTIONAL AND TRANSLATIONAL INITIATION SITES OF IS50 CONTROL OF TRANSPOSASE AND INHIBITOR EXPRESSION
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DOI：
10.1016/0022-2836(86)90028-8
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发表时间：
1986-12-20
影响因子：
5.6
通讯作者：
REZNIKOFF, WS
中科院分区：
文献类型：
--
作者：
KREBS, MP;REZNIKOFF, WS
我们检查了负责IS50R编码的转座酶和转座抑制蛋白表达的转录起始位点，并确定了转座酶可能的翻译起始位点。转座酶-β-半乳糖苷酶融合蛋白的氨基末端分析给出序列Met-Ile-Thr-Ser-Ala，其对应于从IS50的位置93开始的预测氨基酸序列。体内产生的 IS50 RNA 的 S1 核酸酶图谱表明，三个转录物 T1、T2 和 T3 起始于该位置附近。只有 T1 从转座酶氨基末端上游开始。 T2 对应于先前描述的体外转录本。对 IS50-lacZ 构建体的缺失衍生物产生的转录物和蛋白质的分析表明，这三个转录物起始于聚集在 IS50 末端附近的独立但重叠的启动子。该分析证实只有 T1 可以编码转座酶，而 T2 主要负责抑制蛋白的表达。 T3 的编码能力尚未确定。最后，源自 IS50 之外的转录本被阻止表达转座酶，因为二级结构仅存在于这些转录本中。
We have examined transcriptional start sites responsible for expression of the transposase and transposition inhibitor proteins encoded by IS50R, and determined the likely translational start site of transposase. Amino-terminal analysis of a transposase-.beta.-galactosidase fusion protein gave the sequence Met-Ile-Thr-Ser-Ala, which corresponds to the predicted amino acid sequence starting at position 93 of IS50. S1 nuclease mapping of IS50 RNA produced in vivo indicated that three transcripts, T1, T2 and T3, start near this position. Only T1 starts upstream from the transposase amino terminus. T2 corresponds to an in-vitro transcript described previously. Analysis of the transcripts and proteins produced from deletion derivatives of an IS50-lacZ construct suggested that the three transcripts initiate at independent but overlapping promoters clustered near the end of IS50. This analysis confirmed that only T1 can encode transposase, and that T2 is largely responsible for expression of the inhibitor protein. The coding capacity of T3 was not determined. Finally, transcripts that originate outside of IS50 are prevented from expressing transposase because of a secondary structure that is present in these transcripts only.