Engineering of homologous recombination hotspots with AU-rich sequences in brome mosaic virus
Engineering of homologous recombination hotspots with AU-rich sequences in brome mosaic virus
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DOI：
10.1128/jvi.71.5.3799-3810.1997
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发表时间：
1997-05-01
影响因子：
5.4
通讯作者：
Bujarski, JJ
中科院分区：
文献类型：
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作者：
Nagy, PD;Bujarski, JJ
以前，我们观察到在雀麦花叶溴病毒（BMV）的遗传重组过程中，RNA重组体的交叉位点聚集在富含AU的区域内或附近（P. D. Nagy和J. J. Bujarski。J. Virol. 70：415-426，1996）。为了测试富含AU的序列是否可以促进同源重组，将富含AU的序列引入亲本BMV RNA（RNA 2和RNA 3）中。这些插入产生了同源RNA 2-RNA 3重组热点。另外两个富含AU的序列也支持高频同源重组，如果具有高或平均GIC含量的共同序列紧邻富含AU的元件的上游存在。同源RNA重组不需要任何额外的序列基序或RNA结构，并且在3'非编码区内是非位置特异性的。这些结果表明核苷酸含量（即，共同的5 ′ GC富集区或中等AU富集区和3 ′ AU富集区的存在）是决定同源重组位点的重要因素。一种机制，涉及复制酶切换过程中的正义RNA链的合成来解释所观察到的结果。
Previously, we observed that crossovers sites of RNA recombinants clustered within or close to AU-rich regions during genetic recombination in brome mosaic bromovirus (BMV) (P. D. Nagy and J. J. Bujarski. J. Virol. 70:415-426, 1996). To test whether AU-rich sequences can facilitate homologous recombination, AU-rich sequences were introduced into parental BMV RNAs (RNA2 and RNA3). These insertions created a homologous RNA2-RNA3 recombination hotspot. Two other AU-rich sequences also supported high-frequency homologous recombination if a common sequence with high or average GIC content was present immediately upstream of the AU-rich element. Homologous RNA recombination did not require any additional sequence motifs or RNA structures and was position nonspecific within the 3' noncoding region. These results suggest that nucleotide content (i.e., the presence of common 5' GC-rich or moderately AU-rich and 3' AU-rich regions) is the important factor that determines the sites of homologous recombination. A mechanism that involves replicase switching during synthesis of positive-sense RNA strands is presented to explain the observed results.