The Effect of an Alternate Start Codon on Heterologous Expression of a PhoA Fusion Protein in Mycoplasma gallisepticum
The Effect of an Alternate Start Codon on Heterologous Expression of a PhoA Fusion Protein in Mycoplasma gallisepticum
复制标题
DOI：
10.1371/journal.pone.0127911
复制
发表时间：
2015-05-26
期刊：
影响因子：
3.7
通讯作者：
Markham, Philip F.
中科院分区：
文献类型：
--
作者：
Panicker, Indu S.;Browning, Glenn F.;Markham, Philip F.
虽然许多支原体种属的基因组已被测序，但没有翻译起始密码子使用的整理数据，并且尚未研究替代起始密码子对基因表达的影响。注释基因组的分析发现，ATG是支原体属中最普遍的翻译起始密码子。然而，在鸡毒支原体中，GTG起始密码子通常用于vlhA多基因家族，其编码高度丰富的时相可变脂蛋白粘附素。因此，在M.鸡败血症起始密码子从ATG突变为GTG导致phoA报告基因的转录水平降低2.5倍，但含有phoA与GTG起始密码子的转化体中的phoA活性水平仅为含有phoA与ATG起始密码子的转化体的63%，表明GTG是更有效的翻译起始密码子。phoA报告基因表达中翻译起始密码子交换的影响在M.鸡毒支原体的翻译起始过程与以前在大肠杆菌或枯草芽孢杆菌中看到的翻译起始过程相比，表明支原体中的翻译起始过程可能与其他细菌中使用的翻译起始过程有一些显著差异。这是第一次研究支原体中的翻译起始密码子使用和使用替代起始密码子对这些细菌表达的影响。
While the genomes of many Mycoplasma species have been sequenced, there are no collated data on translational start codon usage, and the effects of alternate start codons on gene expression have not been studied. Analysis of the annotated genomes found that ATG was the most prevalent translational start codon among Mycoplasma spp. However in Mycoplasma gallisepticum a GTG start codon is commonly used in the vlhA multigene family, which encodes a highly abundant, phase variable lipoprotein adhesin. Therefore, the effect of this alternate start codon on expression of a reporter PhoA lipoprotein was examined in M. gallisepticum. Mutation of the start codon from ATG to GTG resulted in a 2.5 fold reduction in the level of transcription of the phoA reporter, but the level of PhoA activity in the transformants containing phoA with a GTG start codon was only 63% of that of the transformants with a phoA with an ATG start codon, suggesting that GTG was a more efficient translational initiation codon. The effect of swapping the translational start codon in phoA reporter gene expression was less in M. gallisepticum than has been seen previously in Escherichia coli or Bacillus subtilis, suggesting the process of translational initiation in mycoplasmas may have some significant differences from those used in other bacteria. This is the first study of translational start codon usage in mycoplasmas and the impact of the use of an alternate start codon on expression in these bacteria.