Regulation of citrate‐dependent iron transport of Escherichia coli: FecR is required for transcription activation by Feel
Regulation of citrate‐dependent iron transport of Escherichia coli: FecR is required for transcription activation by Feel
复制标题
大肠杆菌柠檬酸依赖性铁转运的调节：Feel 转录激活需要 FecR
作者：
M. Ochs;S. Veitinger;Insook Kim;D. Weiz;A. Angerer;V. Braun
铁和柠檬酸盐诱导铁- 3+转运到大肠杆菌K - 12。诱导剂可能是二磷酸铁，它不需要被吸收到细胞质中来诱导铁转运基因的转录。诱导需要两个调控基因，fed和fecR，位于fecABCDE转运基因的上游。我们报道，在体内，染色体编码的Feel蛋白激活了fecA和fecB转运基因的转录，以响应柠檬酸铁和FecR蛋白。表达染色体和质粒编码的截断的铁铁衍生物的细胞不再对柠檬酸铁有反应，而是组成性地表达铁铁转运基因。最小的活性FecR衍生物含有59个氨基酸残基，而野生型FecR含有317个氨基酸残基。本构诱导低于柠檬酸铁对野生型菌株的诱导。结果表明，FecR的N端部分激活了Feel，而C端部分对柠檬酸铁有响应。fee转运基因的转录受Feel和FecR的正调控，而受Fe2+‐Fur抑制因子的负调控。转录激活和抑制可能相互独立地发生。
Citrate‐dependent Fe3+ transport into Escherichia coli K‐12 is induced by iron and citrate. The inducer is probably ferric dicitrate which does not have to be taken up into the cytoplasm to induce transcription of the fec transport genes. Two regulatory genes, fed and fecR, located upstream of the fecABCDE transport genes, are required for induction. We report that in vivo the chromosomally encoded Feel protein activates transcription of the fecA and fecB transport genes in response to ferric citrate and the FecR protein. Cells expressing chromosomally and plasmid‐encoded truncated FecR derivatives no longer responded to ferric citrate and expressed the fec transport genes constitutively. The smallest active FecR derivative contained 59 amino acid residues as compared to the 317 residues of wild‐type FecR. Constitutive induction was lower than induction of the FecR wild‐type strain by ferric citrate. It is concluded that the N‐terminal portion of FecR activates Feel and that the C‐terminal portion of FecR responds to ferric citrate. Transcription of the fee transport genes is positively regulated by Feel and FecR and negatively regulated by the Fe2+‐Fur repressor. Transcription activation and repression may occur independently of each other.
DOI：
10.1073/pnas.82.4.1074
发表时间：
1985-01-01
影响因子：
11.1
作者：
TABOR, S;RICHARDSON, CC
通讯作者：
RICHARDSON, CC