THE ESCHERICHIA-COLI FMT GENE, ENCODING METHIONYL-TRANSFER RNAFMET FORMYLTRANSFERASE, ESCAPES METABOLIC CONTROL
THE ESCHERICHIA-COLI FMT GENE, ENCODING METHIONYL-TRANSFER RNAFMET FORMYLTRANSFERASE, ESCAPES METABOLIC CONTROL
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DOI：
10.1128/jb.175.4.993-1000.1993
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发表时间：
1993-02-01
影响因子：
3.2
通讯作者：
BLANQUET, S
中科院分区：
文献类型：
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作者：
MEINNEL, T;GUILLON, JM;BLANQUET, S
最近克隆的 fmt 基因附近的遗传组织已被研究，该基因编码大肠杆菌甲硫氨酰-tRNA(f)Met 甲酰基转移酶（J. M. Guillon, Y. Mechulam, J. M. Schmitter, S. Blanquet, and G. Fayat, J. Bacteriol. 174:4294-4301, 1992）。 fmt 基因以 GUG 密码子开始，与另一个基因 fins 共转录，并且该操纵子的转录起始位点已被精确定位。此外，fmt 上游 1,379 bp 片段的核苷酸序列揭示了两个额外的开放阅读框，极性相反。在每小时 0.3 至 2 次倍增的范围内，细胞内甲硫氨酰-tRNA(f)Met 甲酰基转移酶浓度保持恒定，据我们所知，这是蛋白质合成装置的基因成分逃脱代谢控制的第一个例子。当使用基因融合技术进行探测时，没有发现甲硫氨酰-tRNA(f)Met甲酰基转移酶或tRNA(f)Met浓度对fmt表达的影响。讨论了 fmt 基因（其产物过量存在以确保甲硫氨酰-tRNA(f)Met 完全 N 酰化）可以以组成型方式表达的可能性。
The genetic organization near the recently cloned fmt gene, encoding Escherichia coli methionyl-tRNA(f)Met formyltransferase (J. M. Guillon, Y. Mechulam, J. M. Schmitter, S. Blanquet, and G. Fayat, J. Bacteriol. 174:4294-4301, 1992), has been studied. The fmt gene, which starts at a GUG codon, is cotranscribed with another gene, fins, and the transcription start site of this operon has been precisely mapped. Moreover, the nucleotide sequence of a 1,379-bp fragment upstream from fmt reveals two additional open reading frames, in the opposite polarity. In the range of 0.3 to 2 doublings per h, the intracellular methionyl-tRNA(f)Met formyltransferase concentration remains constant, providing, to our knowledge, the first example of a gene component of the protein synthesis apparatus escaping metabolic control. When the gene fusion technique was used for probing, no effect on fmt expression of the concentrations of methionyl-tRNA(f)Met formyltransferase or tRNA(f)Met could be found. The possibility that the fmt gene, the product of which is present in excess to ensure full N acylation of methionyl-tRNA(f)Met, could be expressed in a constitutive manner is discussed.