Highly diverse intergenic regions of the paramyxovirus simian virus 5 cooperate with the gene end U tract in viral transcription termination and can influence reinitiation at a downstream gene.
Highly diverse intergenic regions of the paramyxovirus simian virus 5 cooperate with the gene end U tract in viral transcription termination and can influence reinitiation at a downstream gene.
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副粘病毒猿病毒 5 的高度多样化的基因间区域与病毒转录终止中的基因末端 U 道配合，并且可以影响下游基因的重新启动。
DOI：
10.1128/jvi.73.5.3904-3912.1999
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发表时间：
1999
影响因子：
5.4
通讯作者：
Parks,GD
中科院分区：
文献类型：
--
作者：
Rassa,JC;Parks,GD
一个包含M-F基因连接的双顺反子微型基因组被用来确定猴病毒5（SV 5）基因间区域在转录中的作用。M-F连接点与其他SV 5连接点的不同之处在于具有仅4个残基的短M基因末端U段（U4段）和在M基因末端与F基因起始位点之间的22个碱基的M-F基因间序列。用非病毒序列替换22个碱基的M-F基因间区域导致在M基因末端终止缺陷的微型基因组模板（Rep 22）。有效的M基因终止可以以两种方式中的任一种恢复到突变体Rep 22模板：通过将U道长度从4个残基增加到6个残基或通过恢复野生型（WT）U4道的紧下游的G残基。在双顺反子SH-HN微型基因组中，U4-G组合在指导SH转录终止方面在功能上等同于天然存在的SH U6-A基因末端。除了影响终止外，M-F基因间区也影响聚合酶的再起始。在WT U4-GM基因末端的背景下，将非病毒序列取代到M-F基因间区域中对F基因再起始具有不同的影响，其中一些但不是所有的非病毒序列抑制再起始。F基因再起始的抑制与具有高C含量的外源序列相关。在22个碱基的M-F基因间片段的中间删除6个碱基或插入18个额外的核苷酸并不影响M基因的终止或F基因的重新起始，表明M-F基因间长度本身不是调节SV 5聚合酶活性的重要因素。我们的研究结果表明，在SV 5基因连接的序列多样性反映了特定的组合，可能差异影响SV 5基因的表达，并提供了一个额外的水平的转录控制超出了从3′端启动子的基因的距离。
A dicistronic minigenome containing the M-F gene junction was used to determine the role of the simian virus 5 (SV5) intergenic regions in transcription. The M-F junction differs from the other SV5 junctions by having a short M gene end U tract of only four residues (U4 tract) and a 22-base M-F intergenic sequence between the M gene end and F gene start site. Replacing the 22-base M-F intergenic region with nonviral sequences resulted in a minigenome template (Rep 22) that was defective in termination at the end of the M gene. Efficient M gene termination could be restored to the mutant Rep 22 template in either of two ways: by increasing the U tract length from four to six residues or by restoring a G residue immediately downstream of the wild-type (WT) U4 tract. In a dicistronic SH-HN minigenome, a U4-G combination was functionally equivalent to the naturally occurring SH U6-A gene end in directing SH transcription termination. In addition to affecting termination, the M-F intergenic region also influenced polymerase reinitiation. In the context of the WT U4-G M gene end, substituting nonviral sequences into the M-F intergenic region had a differential effect on F gene reinitiation, where some but not all nonviral sequences inhibited reinitiation. The inhibition of F gene reinitiation correlated with foreign sequences having a high C content. Deleting 6 bases or inserting 18 additional nucleotides into the middle of the 22-base M-F intergenic segment did not influence M gene termination or F gene reinitiation, indicating that M-F intergenic length per se is not a important factor modulating the SV5 polymerase activity. Our results suggest that the sequence diversity at an SV5 gene junction reflects specific combinations which may differentially affect SV5 gene expression and provide an additional level of transcriptional control beyond that which results from the distance of a gene from the 3′ end promoter.