Cell size and nucleoid organization of engineered Escherichia coli cells with a reduced genome
Cell size and nucleoid organization of engineered Escherichia coli cells with a reduced genome
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DOI：
10.1111/j.1365-2958.2004.04386.x
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发表时间：
2005-01-01
影响因子：
3.6
通讯作者：
Kato, J
中科院分区：
文献类型：
--
作者：
Hashimoto, M;Ichimura, T;Kato, J
基因组的最小化对于通过实验鉴定最小基因集是必要的，该最小基因集仅包含那些对于维持功能细胞至关重要且足以维持的基因。遗传技术的最新发展使得产生基因组显着减少的细菌成为可能。我们开发了一个用于形成无标记染色体缺失的简单系统，并构建和表征了一系列大规模的大肠杆菌染色体缺失突变体，这些突变体缺乏 2.4% 至 29.7% 的亲本染色体。结合缺失突变会改变细胞的长度和宽度，具有较大缺失的突变细胞甚至比亲代细胞更长更宽。突变体的类核组织也发生了变化：类核以多个小核的形式出现，并且位于包膜附近的外围。翻译的抑制导致它们凝结成一两个堆积的核仁，这表明膜蛋白的转录和翻译的耦合位于染色体的外围。由于这些表型与球形细胞相似，因此可能是形态变化的结果。基于观察到的这些突变体的核定位，我们讨论了细胞核动力学。
The minimization of a genome is necessary to identify experimentally the minimal gene set that contains only those genes that are essential and sufficient to sustain a functioning cell. Recent developments in genetic techniques have made it possible to generate bacteria with a markedly reduced genome. We developed a simple system for formation of markerless chromosomal deletions, and constructed and characterized a series of large-scale chromosomal deletion mutants of Escherichia coli that lack between 2.4 and 29.7% of the parental chromosome. Combining deletion mutations changes cell length and width, and the mutant cells with larger deletions were even longer and wider than the parental cells. The nucleoid organization of the mutants is also changed: the nucleoids occur as multiple small nucleoids and are localized peripherally near the envelope. Inhibition of translation causes them to condense into one or two packed nucleoids, suggesting that the coupling of transcription and translation of membrane proteins peripherally localizes chromosomes. Because these phenotypes are similar to those of spherical cells, those may be a consequence of the morphological change. Based on the nucleoid localization observed with these mutants, we discuss the cellular nucleoid dynamics.