PHOSPHATE REGULATION OF GENES IN ESHERICHIA COLI

Pho调节子的PI控制是一种跨膜信号 转导。PI控制需要Phou、Phob、Phor和绑定 依赖蛋白质的PstSCAB，PI转运体。PstSCAB-Phou和 在PI限制期间，PhoBR操纵子被解压100倍。太平洋司令部 Transporter和Phou具有负面的调节作用。显然，一个 当所有PstSCAB都来自PST转运体时，PI抑制信号从PST转运体流出 复合体被PI浸透，无论有多少(被抑制 条件)或许多(减压条件)复合体存在。这 信号以某种方式传递，可能通过Phou传递到Phor，进而 充当PI传感器。 PHOB和PHOR是双组分监管大家庭的成员 细菌中的系统。PHOB是一种DNA结合蛋白，可转录 激活剂。PHOR是一种自磷酸酶，是PHOB的一种激酶，以及 (推测)Phob-PI的一种磷酸酶；它将Phob在其 转录活性(Phob-PI)和非活性(游离型Phob)形式。这个 PhoBR操纵子是不寻常的，因为它同时受制于转录和 翻译控制；后者似乎涉及一种形式的反义 受生理调节的RNA控制。 这一建议涉及PI跨膜信号的机制 涉及PstSCAB转运体、Phou和Phor的转导 控制光子BR操纵子。分子遗传学研究旨在 定义PI控制涉及哪些组件并确定如何 他们相互作用。野生型和突变型蛋白的生化研究 旨在检测关键的蛋白质-蛋白质相互作用 从对抑制子突变的分析中预测。关于中国石油天然气集团公司 PstSCAB-Phou和PhoBR操纵子的表达被设计为 确定关键基因产物的数量如何影响PI控制和 每个操纵子中都有哪些重要的调控信号。这些 对PHO调节子的PI控制进行了研究，旨在为 仅限于我们对细胞如何调节磷同化基因的理解 而是细胞一般如何识别环境刺激。

Pi control of the PHO regulon is a form of transmembrane signal transduction. Pi control requires PhoU, PhoB, PhoR, and the binding protein-dependent PstSCAB, Pi transporter. Both the pstSCAB-phoU and phoBR operons are derepressed 100-fold during Pi limitation. The Pst transporter and PhoU have negative regulatory roles. Apparently, a signal for Pi repression flows from the Pst transporter when all PstSCAB complexes are saturated with Pi, regardless of how few (repressed condition) or many (derepressed condition) complexes are present. This signal is somehow communicated, perhaps via PhoU, to PhoR which in turn acts as the Pi sensor. PhoB and PhoR are members of the large family of two-component regulatory systems in bacteria. PhoB is a DNA-binding protein and transcriptional activator. PhoR is an autophosphorylase, a kinase for PhoB, and (presumably) a phosphatase for PhoB-Pi; it converts PhoB between its transcriptionally active (PhoB-Pi) and inactive (free PhoB) forms. The phoBR operon is unusual because it is subject both to transcriptional and translational controls; the latter appears to involve a form of antisense RNA control that is physiologically regulated. This proposal concerns the mechanism of Pi transmembrane signal transduction involving the PstSCAB transporter, PhoU, and PhoR, and control of the phoBR operon. Molecular genetic studies are designed to define what components are involved in Pi control and determining how they interact. Biochemical studies on wild-type and mutant proteins are designed to detect critical protein-protein interactions that are predicted from an analysis of suppressor mutations. Studies on the expression of the pstSCAB-phoU and phoBR operons are designed to determine how the amounts of key gene products affects Pi control and what significant regulatory signals occur within each operon. These studies on Pi control of the PHO regulon are designed to contribute not only to our understanding of how cells regulate genes for P assimilation but also how cells recognize environmental stimuli in general.