A Switch in Gene Expression During Bacterial Development

细菌发育过程中基因表达的转变

• 批准号: 8289907
• 负责人: Amy Hitchcock Camp
• 金额: $ 27.58万
• 依托单位: MOUNT HOLYOKE COLLEGE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8289907
• 关键词: Address; Antibiotics; Bacillus anthracis; Bacillus subtilis; Bacteria; Binding; Biochemical; Biological; Biological Models; Cells; Clostridium difficile; Cues; DNA-Directed RNA Polymerase; Data; Development; Developmental Biology; Developmental Cell Biology; Developmental Gene; Disease; Eukaryotic Cell; Event; Gene Activation; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Genetic; Genetic Transcription; Global Change; Goals; Growth and Development function; Hallmark Cell; Knowledge; Laboratory Research; Light; Malignant Neoplasms; Mediating; Messenger RNA; Mission; Modeling; Molecular; Normal Cell; Outcome; Pathogenesis; Pathway interactions; Phenotype; Prokaryotic Cells; Proteins; Regulation; Reproduction spores; Research; System; Tars; Testing; Time; Transcription Initiation Site; Transcriptional Regulation; Translational Regulation; Universities; Vent; Work; base; cancer cell; cell growth; cell type; cellular development; developmental disease; extracellular; graduate student; innovation; insight; metaplastic cell transformation; novel; pathogen; prevent; programs; research study; response; undergraduate student

DESCRIPTION (provided by applicant): Eukaryotic and prokaryotic cells alike possess the remarkable ability to alter their phenotypes through global changes in gene expression. The proper execution of transitions in gene expression is critical for cellular "transformation", eithe as part of normal cell and developmental biology, or, abnormally, as during the conversion of a normal cell to a cancer cell. In bacteria, transitions in gene expression programs drive phenotypic changes critical for growth, development, and pathogenesis. Despite their importance, there are few examples of transitions in gene expression that are understood in molecular detail from beginning to end. In order to close this critical gap in knowledge, we will elucidate the molecular mechanisms that control the switch from early (¿F-directed) to late (¿G-directed) transcription in the developing Bacillus subtilis spore. Broadly speaking, the transition to a new gene expression program requires not only that the new program is induced, but also that the old gene expression program is deactivated. While significant effort has been placed on identifying the mechanisms that activate ¿G, very little is known of the mechanisms by which ¿F is deactivated and how these two events are coordinated. The central hypothesis of our study is that proper transition from ¿F to ¿G requires regulatory mechanisms to first prevent ¿G activity at early times and subsequently to disarm the ¿F protein at or before the switch to late gene expression. We will test this central hypothesis using a combination of genetic, biochemical, and cell-biological approaches. In Specific Aim 1, we will determine the mechanism by which ¿G activity is restricted at early times. The working hypothesis for this aim is that negative transcriptional or translational regulation prevents significant accumulation of ¿G protein prior t the switch to late gene expression. In Specific Aim 2, we will identify the mechanism by which F in - a small, conserved protein required for the switch from ¿F to ¿G - disarms . Finally, in Specific Aim 3, we will distinguish two competing models for a second, ¿G -dependent but Fin- independent, mechanism of ¿F inhibition: that ¿G outcompetes ¿F for access to RNA polymerase or, alter- natively, that ¿G mediates ¿F inhibition via activation of one or more target genes. In all, the expected out- come of the proposed research is significant mechanistic insight into how the switch from ¿F - to ¿G-directed gene expression is achieved in the developing B. subtilis spore. This contribution will be significant because it will address a fundamental, yet currently inadequately answered question in cell and developmental biology: How, at the molecular level, do cells shed their old identity while simultaneously taking on a new one? Moreover, this study has the potential to identify novel antibiotic targets for gram-positive spore forming bacterial pathogens such as Bacillus anthracis and Clostridium difficile. Finally, this research plan is innovative not only because it addresses largely overlooked aspects of gene expression switches, but also because it will be carried out exclusively by graduate and undergraduate students. PUBLIC HEALTH RELEVANCE: Properly regulated transitions in gene expression are critical for normal cellular growth and development, as well as for bacterial pathogenesis. Here we will elucidate the molecular mechanisms that control the switch from early to late developmental transcription during spore formation by the bacterium Bacillus subtilis, a premier model system for studies of regulation. This project is relevant to NIH's mission because it will address a fundamental, yet currently inadequately understood aspect of cell and developmental biology, and, furthermore, has significant potential to identify novel antibiotic targets in gram-positive spore-forming bacterial pathogens such as Bacillus anthracis and Clostridium difficile.

描述（由应用提供）：真核和原核细胞都具有通过基因表达的全球变化改变其表型的显着能力。基因表达中过渡的适当执行对于正常细胞和发育生物学的一部分，或者绝对，如正常细胞转化为癌细胞时，对细胞“转化”至关重要。在细菌中，基因表达程序中的过渡驱动表型变化对于生长，发育和发病机理至关重要。尽管它们的重要性，但很少有基因表达过渡的例子从头到尾就以分子细节来理解。为了缩小知识的关键差距，我们将阐明从发育中的枯草芽孢杆菌酱中控制从早期（f定位）到晚期转录的分子机制。从广义上讲，过渡 对于一个新的基因表达程序，不仅要求诱导新程序，而且还要求旧的基因表达程序被停用。尽管在识别激活`g的机制方面已付出了重大努力，但对``f'f的机制几乎不知所措，而``f被停用了，以及这两个事件的协调方式。我们研究的核心假设是，从»f到g的适当过渡需要调节机制，以便在早期，然后在转换为晚期基因表达的灾难时首先防止e g活性。我们将使用遗传，生化和细胞生物学方法的结合来检验这一中心假设。在特定的目标1中，我们将确定在早期限制活动的机制。此目标的工作假设是，负转录或翻译调节可以防止在转到晚期基因表达之前的G蛋白的显着积累。在特定的目标2中，我们将确定F in -in -in -f in -f in`f in`f in`f in到g- dismans所需的小蛋白质所需的机制。最后，在特定目标3中，我们将在第二个竞争模型中区分两种竞争模型，``g-依赖性但独立的，机制'f抑制作用：``g ovepetes'f ovetepetes'f用于访问RNA聚合酶或替代性的，或者改变，这是通过激活一个或多个目标的抑制作用来介导的。 基因。总的来说，提出的研究的预期范围是关于如何在发展中的枯草芽孢杆菌酱中实现从«f-指导基因表达的转换的重要机理洞察力。这项贡献将是重要的，因为它将解决细胞和发育生物学中目前的基本但目前不足的问题：在分子水平上，细胞在同时又进行新的身份时如何脱离旧身份？此外，这项研究有可能鉴定出革兰氏阳性变质的新型抗生素靶标，形成细菌病原体，例如炭疽芽孢杆菌和艰难梭菌。最后，该研究计划具有创新性，这不仅是因为它解决了基因表达开关的很大程度上忽略的方面，还因为它将仅由研究生和本科生进行。 公共卫生相关性：基因表达中适当调节的转变对于正常的细胞生长和发育以及细菌发病机理至关重要。 Here we will elucidate the molecular mechanisms that control the switch from early to late developmental transcription during scatter formation by the bacteria Bacillus subtilis, a premier model system for studies of regulation.该项目与NIH的使命相关，因为它将解决细胞和发育生物学方面的基本，但目前不足的了解，并且具有巨大的潜力，可以在革兰氏阳性孢子形成的细菌病原体（例如嗜酸芽孢杆菌和艰难梭菌）中识别新型的抗生素靶标。

项目成果

Transcription and translation of the sigG gene is tuned for proper execution of the switch from early to late gene expression in the developing Bacillus subtilis spore.

• DOI: 10.1371/journal.pgen.1007350
• 发表时间: 2018-04
• 期刊: PLoS genetics
• 影响因子: 4.5
• 作者: Mearls EB;Jackter J;Colquhoun JM;Farmer V;Matthews AJ;Murphy LS;Fenton C;Camp AH
• 通讯作者: Camp AH

Structural and Functional Insights into Bacillus subtilis Sigma Factor Inhibitor, CsfB.

• DOI: 10.1016/j.str.2018.02.007
• 发表时间: 2018-04-03
• 期刊: Structure (London, England : 1993)
• 作者: Martínez-Lumbreras S;Alfano C;Evans NJ;Collins KM;Flanagan KA;Atkinson RA;Krysztofinska EM;Vydyanath A;Jackter J;Fixon-Owoo S;Camp AH;Isaacson RL
• 通讯作者: Isaacson RL