Involvement of the Escherichia coli folate-binding protein YgfZ in RNA modification and regulation of chromosomal replication initiation
Involvement of the Escherichia coli folate-binding protein YgfZ in RNA modification and regulation of chromosomal replication initiation
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DOI：
10.1111/j.1365-2958.2005.04932.x
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发表时间：
2006-01-01
影响因子：
3.6
通讯作者：
Kato, J
中科院分区：
文献类型：
--
作者：
Ote, T;Hashimoto, M;Kato, J
大肠杆菌hda基因编码DnaA相关蛋白，其对于DnaA的调节失活（RIDA）（控制染色体复制起始的系统）是必需的。我们已经确定了ygfZ基因，它编码叶酸结合蛋白，作为hda突变的抑制因子。ygfZ无效突变抑制hda无效突变。在hda ygfZ背景下，由hda突变赋予的过度起始和失败延伸表型被部分抑制。在hda突变体中，活性形式的DnaA，ATP-DnaA的积累被ygfZ基因的破坏所抑制，表明YgfZ参与调节ATP-DnaA的水平。虽然ygfZ不是必需基因，但ygfZ破坏物生长缓慢，特别是在低温下，表明该基因对细胞增殖很重要。我们已经鉴定了mnmE（trmE）作为ygfZ破坏的抑制剂。该基因编码一个参与tRNA修饰的GTP酶。对ygfZ突变体中RNA修饰的检查揭示了2-甲硫基-6-碘脱氧腺苷水平的降低，表明YgfZ参与了某些tRNA中这种修饰核苷的甲硫基形成。这些结果表明，YgfZ是通过tRNA修饰发挥作用的调控网络中的关键因素。
The Escherichia coli hda gene codes for a DnaA-related protein that is essential for the regulatory inactivation of DnaA (RIDA), a system that controls the initiation of chromosomal replication. We have identified the ygfZ gene, which encodes a folate-binding protein, as a suppressor of hda mutations. The ygfZ null mutation suppresses an hda null mutation. The over-initiation and abortive elongation phenotypes conferred by the hda mutations are partially suppressed in an hda ygfZ background. The accumulation of the active form of DnaA, ATP-DnaA, in the hda mutant is suppressed by the disruption of the ygfZ gene, indicating that YgfZ is involved in regulating the level of ATP-DnaA. Although ygfZ is not an essential gene, the ygfZ disruptant grows slowly, especially at low temperature, demonstrating that this gene is important for cellular proliferation. We have identified mnmE (trmE) as a suppressor of the ygfZ disruption. This gene encodes a GTPase involved in tRNA modification. Examination of RNA modification in the ygfZ mutant reveals reduced levels of 2-methylthio-6-iodeadenosine, indicating that YgfZ participates in the methylthio-group formation of this modified nucleoside in some tRNAs. These results suggest that YgfZ is a key factor in regulatory networks that act via tRNA modification.