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首页> 外文学位 >The Role of the DNA Uptake Sequence in Natural Transformation of the Obligate Human Pathogen Neisseria gonorrhoeae.
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The Role of the DNA Uptake Sequence in Natural Transformation of the Obligate Human Pathogen Neisseria gonorrhoeae.

机译：DNA摄取序列在专性人类病原淋病奈瑟氏球菌自然转化中的作用。

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摘要

Natural transformation is the main means of horizontal genetic exchange in the obligate human pathogen Neisseria gonorrhoeae. Neisseria spp. have been shown to preferentially take up and transform their own DNA by recognizing the nonpalindromic 10- or 12-nucleotide sequence 5'-ATGCCGTCTGAA-3', termed the DNA uptake sequence (DUS). This thesis investigates the effects of the DUS on transformation and DNA uptake for two laboratory strains of N. gonorrhoeae. I found that both strains showed efficient transformation of DUS containing DNA but that the level of transformation with DNA lacking a DUS (DUS0) was variable in the different strains. The DUS-enhanced transformation was 20-fold in strain FA1090, but was approximately 150-fold in strain MS11. Both strains tested provide some level of DUS0 transformation, and DUS0 transformation was type IV pilus dependent. Competition with plasmid DNA revealed that transformation of MS11 was enhanced by the addition of excess plasmid DNA containing a DUS while FA1090 transformation was competitively inhibited. Although FA1090 was able to mediate much more efficient transformation of DNA lacking a DUS than was MS11, DNA uptake experiments showed similar levels of uptake of DNA containing and lacking a DUS in FA1090 and MS11. DNA uptake was competitively inhibited in both FA1090 and MS11; supporting the notion that DNA uptake is similar in both FA1090 and MS11 and is enhanced by the DUS. Transported DNA is processed in the periplasm and the resultant nucleotides are incorporated into the chromosome during replication. DUS recognition leading to DNA uptake is dependent on the inner membrane protein ComA in FA1090, but not in MS11, suggesting other strain-dependent differences during transformation. Investigations into single-stranded DNA (ssDNA) transformation revealed that ssDNA transformation is less efficient than matched dsDNA transformation, and there is a recombination bias for the coding strand of the transforming DNA gyrB1. Furthermore, one strand of the DUS is much more active to enhance ssDNA transformation compared to the other strand of the DUS. Taken together, these data indicate that the role of the DUS during DNA transformation is variable between strains of N. gonorrhoeae and that the DUS has multiple roles during transformation.
机译：自然转化是专性人类病原体淋病奈瑟氏球菌中水平基因交换的主要手段。奈瑟菌属已显示通过识别非回文的10或12核苷酸序列5'-ATGCCGTCTGAA-3'（称为DNA吸收序列（DUS））优先吸收和转化自己的DNA。本文研究了DUS对两种淋病奈瑟氏球菌实验室菌株转化和DNA吸收的影响。我发现两种菌株均能有效地转化含有DUS的DNA，但在不同菌株中，缺乏DUS（DUS0）的DNA的转化水平却是可变的。 DUS增强的转化在FA1090菌株中是20倍，但在MS11菌株中是约150倍。所测试的两种菌株均提供一定水平的DUS0转化，并且DUS0转化是IV型菌毛依赖性的。与质粒DNA的竞争显示，通过添加过量的含有DUS的质粒DNA可以增强MS11的转化，而竞争性抑制FA1090转化。尽管FA1090能够介导缺少DUS的DNA的转化效率比MS11高得多，但DNA吸收实验显示FA1090和MS11中含有和缺乏DUS的DNA的吸收水平相似。 FA1090和MS11都竞争性地抑制了DNA的吸收。支持FA1090和MS11中DNA吸收相似并且DUS增强了DNA吸收的观点。转运的DNA在周质中加工，并且在复制过程中将所得的核苷酸掺入染色体中。 DUS识别导致DNA摄取取决于FA1090中的内膜蛋白ComA，而不取决于MS11，这表明在转化过程中还存在其他依赖菌株的差异。对单链DNA（ssDNA）转化的研究表明，与匹配的dsDNA转化相比，ssDNA转化效率低，并且转化DNA gyrB1的编码链存在重组偏向。此外，与DUS的另一条链相比，DUS的一条链在增强ssDNA转化方面更具活性。综上所述，这些数据表明DUS在淋病奈瑟氏球菌菌株之间的DNA转化过程中的作用是可变的，并且DUS在转化过程中具有多种作用。

著录项

  • 作者

    Duffin, Paul Meyer.;

  • 作者单位

    Northwestern University.;

  • 授予单位 Northwestern University.;
  • 学科 Biology Molecular.;Biology Microbiology.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 199 p.
  • 总页数 199
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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