Nitrogen regulation of the codBA (cytosine deaminase) operon from Escherichia coli by the nitrogen assimilation control protein, NAC.
Nitrogen regulation of the codBA (cytosine deaminase) operon from Escherichia coli by the nitrogen assimilation control protein, NAC.
复制标题
氮同化控制蛋白 NAC 对大肠杆菌 codBA（胞嘧啶脱氨酶）操纵子的氮调节。
DOI：
10.1128/jb.185.9.2920-2926.2003
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发表时间：
2003
影响因子：
3.2
通讯作者：
Bender,RobertA
中科院分区：
文献类型：
--
作者：
Muse,WilsonB;Rosario,ChristopherJ;Bender,RobertA
Transcription of the cytosine deaminase (codBA) operon ofEscherichia coliis regulated by nitrogen, with about three times morecodBAexpression in cells grown in nitrogen-limiting medium than in nitrogen-excess medium. β-Galactosidase expression fromcodBp-lacZoperon fusions showed that the nitrogen assimilation control protein NAC was necessary for this regulation. In vitro transcription from thecodBApromoter with purified RNA polymerase was stimulated by the addition of purified NAC, confirming that no other factors are required. Gel mobility shifts and DNase I footprints showed that NAC binds to a site centered at position −59 relative to the start site of transcription and that mutants that cannot bind NAC there cannot activate transcription. When a longer promoter region (positions −120 to +67) was used, a double footprint was seen with a second 26-bp footprint separated from the first by a hypersensitive site. When a shorter fragment was used (positions −83 to +67), only the primary footprint was seen. Nevertheless, both the shorter and longer fragments showed NAC-mediated regulation in vivo. Cytosine deaminase expression inKlebsiella pneumoniaewas also regulated by nitrogen in a NAC-dependent manner.K. pneumoniaediffers fromE. coliin having two cytosine deaminase genes, an intervening open reading frame between thecodBandcodAorthologs, and a different response to hypoxanthine which increasedcodexpression inK. pneumoniaebut decreased it inE. coli.
