Expression of γ-hemolysin regulated by sae in Staphylococcus aureus strain Smith 5R
Expression of γ-hemolysin regulated by sae in Staphylococcus aureus strain Smith 5R
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DOI：
10.1111/j.1574-6968.2006.00236.x
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发表时间：
2006-06
影响因子：
2.1
通讯作者：
K. Yamazaki;Fuminori Kato;Y. Kamio;J. Kaneko
中科院分区：
文献类型：
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作者：
K. Yamazaki;Fuminori Kato;Y. Kamio;J. Kaneko
金黄色葡萄球菌Smith 5R菌株产生一种双组分致孔毒素，并在人红细胞板(R[+])上形成带有溶血晕环的粗糙表面菌落。该菌株在发酵液中连续传代后，出现γ-溶血素阴性变种，菌落形状光滑(S[−])，S[−]菌株成为优势菌株。在R[+]菌株中，AGRA被插入IS1181基因自然干扰，产生高水平的γ-溶血素。在S[−]突变体中，HLG和Luks-F的mRNAs表达均显著降低。对SAE基因座的核苷酸测序显示，所有分离的S[−]变异株都有SAE基因座的自发突变。通过转化野生型SAE等位基因使γ-溶血素在S[−]中的产量恢复，强烈地表明SAE以一种不依赖于农业的方式正调控γ-溶血素的表达。
Staphylococcus aureus strain Smith 5R produces a two-component pore-forming toxin and forms a rough-surfaced colony with hemolytic haloes on human red blood cell plates (R[+]). Serial subcultures of the strain in broth caused the appearance of γ-hemolysin negative variants with a smooth colony shape (S[−]), and the S[−] valiant became predominant in culture. The R[+] strain, in which agrA is naturally disrupted by an insertion of IS1181, produced high levels of γ-hemolysin. In the S[−] variant, expression of both hlg and lukS-F mRNAs was strongly reduced. Nucleotide sequencing of the sae locus revealed that all isolated S[−] variants had spontaneous mutations in the sae locus. Recovery of γ-hemolysin productivity in S[−] by transformation of the wild-type sae allele strongly suggested that the expression of γ-hemolysin is positively regulated by sae in an agr-independent manner.