权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Modulation of Bacterial Cell Division by (p)ppGpp

(p)ppGpp 对细菌细胞分裂的调节

基本信息

批准号：
10668410
负责人：
Sarah Emily Anderson
金额：
$ 7.18万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-01 至 2024-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10668410
关键词：
Abbreviations Actins Affect Alleles Anabolism Antibiotic Resistance Antibiotics Bacteria Bacterial Physiology Binding Binding Proteins Biochemistry Cell Size Cell Wall Cell division Cell physiology Cells Clinical DNA-Directed RNA Polymerase Data Defect Down-Regulation Enzymes Equilibrium Escherichia coli Fellowship Filament Genetic Transcription Goals Growth Guanosine Triphosphate Phosphohydrolases Lead Learning Length Life Maintenance Mediating Microscopy Modeling Molecular Molecular Machines Mutation Nucleotides Nutrient Nutrient availability Nutritional Phenotype Process Production Proteins Regulation of Cell Size Research Research Personnel Resistance Rod Role Shapes Signaling Molecule Stress Techniques Testing Training Translations Tubulin Work antimicrobial beta-Lactam Resistance beta-Lactams candidate identification career cell growth cell type cellular targeting environmental adaptation knock-down model organism mutant posttranscriptional professor response scaffold

项目摘要

PROJECT SUMMARY/ABSTRACT In bacteria, cell size positively correlates with nutrient availability and negatively correlates with levels of the key nutritional signaling molecules pppGpp and ppGpp (abbreviated (p)ppGpp). (p)ppGpp is produced in response to environmental nutrient limitation and functions primarily to inhibit biosynthesis and slow growth. In the model organism Escherichia coli, (p)ppGpp modulates cell physiology at both the transcriptional and post- transcriptional levels through interactions with RNA polymerase (RNAP) and 56 additional cellular targets. However, the mechanism by which (p)ppGpp contributes to regulation of cell size is not fully understood. The balance between cell division and elongation is a major determinant of size in rod-shaped bacteria. Several pieces of evidence suggest that (p)ppGpp contributes to cell size in part by modulating the balance between these two processes. Increases in (p)ppGpp levels suppress the heat sensitivity of conditional cell division mutants and leads to resistance to mecillinam, an antibiotic targeting the elongation machinery (elongasome). These data suggest that (p)ppGpp positively affects activity of the cell division machinery (divisome). Strains lacking (p)ppGpp ((p)ppGpp0) are ~30% longer than wild-type cells and frequently filament. These phenotypes are not recapitulated in RNAP mutants defective for (p)ppGpp binding, suggesting that (p)ppGpp contributes to cell size through a post-transcriptional interaction with one of its other binding partners. I hypothesize that (p)ppGpp indirectly promotes divisome assembly and activation via interaction with its target proteins. To illuminate the molecular basis of (p)ppGpp mediated changes in divisome and elongasome activity, I propose two complementary aims. In Aim 1, I will characterize the effects of alterations in intracellular (p)ppGpp concentration on production, assembly, and activation of the cell division machinery. In Aim 2, I will screen for (p)ppGpp binding proteins that are required to increase cell length. I will then determine the effect of these proteins on the transcription, translation, assembly, and activity of divisome components (Sub-aim 2b) and, in Sub-aim 2c, determine the mechanism by which candidate proteins modulate cell division. The expected contribution of the proposed work is an enhanced understanding of the mechanisms by which (p)ppGpp modulates bacterial physiology. This contribution is significant because (p)ppGpp is a key component of environmental adaptation throughout the bacterial kingdom. This proposal will also enhance our understanding of (p)ppGpp’s role in intrinsic resistance to the clinically important β-lactam antibiotics, which target components of the divisome and elongasome. In addition, this F32 fellowship will provide me with opportunities to learn new techniques in microscopy and biochemistry, explore new conceptual avenues, and obtain additional professional training that will prepare me for a career as a professor and independent investigator.

项目总结/文摘