OOP RNA, PRODUCED FROM MULTICOPY PLASMIDS, INHIBITS LAMBDA-CII GENE-EXPRESSION THROUGH AN RNASE-III-DEPENDENT MECHANISM
OOP RNA, PRODUCED FROM MULTICOPY PLASMIDS, INHIBITS LAMBDA-CII GENE-EXPRESSION THROUGH AN RNASE-III-DEPENDENT MECHANISM
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DOI：
10.1101/gad.1.9.1005
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发表时间：
1987-11-01
影响因子：
10.5
通讯作者：
WULFF, DL
中科院分区：
文献类型：
--
作者：
KRINKE, L;WULFF, DL
OOP RNA 是一种主要的短转录物（77 个碱基），在体内和体外均由噬菌体 lambda DNA 制成。 OOP RNA 的合成方向与 lambda cII 基因的 mRNA 相反，OOP 区域的最后 55 bp 与 cII 基因的 3' 端重叠。我们发现，含有 OOP DNA 片段的多拷贝质粒可抑制去抑制的原噬菌体的 cII 表达大约 100 倍，使用体内测定，其中 cII 蛋白激活多拷贝质粒上 cII 依赖性启动子的半乳糖激酶合成。当 OOP RNA 的 po 启动子被强 lambda pL 启动子取代时，也观察到很大的抑制作用，但当 po 被删除时则不会。提供大量“抗 OOP”RNA（与 OOP RNA 互补的 RNA）的质粒使得 OOP RNA 成为 cII 表达的不太有效的抑制剂。在缺乏 RNase III 的大肠杆菌菌株中未观察到 OOP DNA 质粒的抑制作用。我们认为 cII mRNA 的 3' 端和 OOP RNA 形成双链复合物，该复合物是宿主酶 RNase III 的底物，导致 cII mRNA 降解。对 OOP DNA 质粒的删除研究表明，抑制作用不需要启动子和终止子茎结构之间的特定序列。在大量过量的抗 OOP RNA 存在下，诱导原噬菌体的 Lambda cII 表达增加两倍。该实验中，原噬菌体是 OOP RNA 的唯一来源，表明 OOP RNA 在调节 cII 基因表达中具有生理作用。
OOP RNA is a major short (77 bases) transcript that is made from bacteriophage lambda DNA both in vivo and in vitro. OOP RNA is synthesized in the opposite direction to mRNA for the lambda cII gene, and the final 55 bp of the OOP region overlaps the 3' end of the cII gene. We find that a multicopy plasmid containing an OOP DNA fragment inhibits cII expression from a derepressed prophage by approximately 100-fold, using an in vivo assay in which cII protein activates galactokinase synthesis from a cII-dependent promoter on a multicopy plasmid. A large inhibitory effect is also observed when the po promoter for OOP RNA is replaced by the strong lambda pL promoter, but not when po is deleted. Plasmids that provide a large excess of "anti-OOP" RNA (RNA that is complementary to OOP RNA) make OOP RNA a less effective inhibitor of cII expression. Inhibition by the OOP DNA plasmid is not observed in an Escherichia coli strain deficient in RNase III. We propose that the 3' end of cII mRNA and OOP RNA form a double-stranded complex that is a substrate for the host enzyme RNase III, resulting in degradation of cII mRNA. Deletion studies on the OOP DNA plasmid indicate that no specific sequence between the promoter and terminator stem structure is required for the inhibitory effect. Lambda cII expression from an induced prophage is increased twofold in the presence of a large excess of anti-OOP RNA. This experiment, in which the prophage is the sole source of OOP RNA, suggests a physiological role for OOP RNA in regulating cII-gene expression.