Genetic Regulation of Bioluminescence in Marine Bacteria

本次调查将重点关注监管的两个方面 来自哈氏弧菌的生物发光（lux）基因：1） 转录的密度依赖性控制;和2） 产生发光变体的机制。 监管 控制发光表达的基因与 操纵子编码用于光产生的酶，并且没有 被克隆了 然而，使用转座子诱变， 在原生生物中，我们已经确定了“丢失的位点”编码 监管职能。 这个未连接的第二个区域，现在 标记转座子插入，将被克隆和遗传 电路分析：特定的lux基因和转录 将对单元进行识别和排序;勒克斯功能将 从突变体表型分析中推断;以及 该区域基因的转录控制将是 使用基因融合进行检查。 众所周知，监管涉及 一种叫做自诱导物的信息素样物质， 分析应该深入了解细菌用来 感知并对环境做出反应。 发光变体 哈维氏弧菌以高频率自发产生， 变回原来的或新的发光形式。 指示 基因组结构的变化与发光有关 通过使用杂交探针已经获得了变异 表示上述第二轨迹的一部分， 来自发光变体的DNA的Southern印迹分析。 我们将 继续克隆整个DNA区域， 并精确定义DNA结构的变化 其影响光发射的强度。 发光的变化可能是一种普遍的 创造所需表型多样性的过程 在各种不断变化的环境中生存 研究这种现象可以丰富我们的 了解基因组可塑性如何产生多样性。

This investigation will focus on two aspects of the regulation of genes for bioluminescence (lux) from Vibrio harveyi: 1) the density-dependent control of transcription; and 2) the mechanism which generates luminous variants. The regulatory genes controlling expression of luminescence are not linked to the operon encoding enzymes for light production and have not been cloned. However, using transposon mutagenesis of the native organism, we have identified the "lost locus" encoding regulatory function(s). This unlinked second region, now marked by transposon insertion, will be cloned and the genetic circuitry analyzed: the specific lux genes and transcriptional units will be identified and sequenced; the Lux functions will be inferred from analysis of mutant phenotypes; and transcriptional control of genes in this region will be examined by using gene fusions. Regulation is known to involve a pheromone-like substance called autoinducer, and genetic analysis should yield insight into mechanisms bacteria use to perceive and react to their environment. Luminous variants of V. harveyi arise spontaneously at high frequencies and can change back to the original or new luminous forms. Indication that changes in genome organization correlate with luminescence variation has been obtained by using a hybridization probe representing part of the second locus mentioned above in Southern blot analysis of DNA from luminous variants. We will proceed to clone the entire region of DNA involved in variation and define precisely the changes in DNA structure which affect the intensity of light emission. Luminous variation could be one manifestation of a general process for creating the diversity of phenotypes needed for survival in the varied and changing circumstances encountered in the ocean, and studying this phenomenon could enrich our understanding of how genome plasticity generates diversity.