The Control of DNA Replication During Sporulation in Bacillus Subtilis PDF Download
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Author: Lilah Lillian Rahn-Lee
Publisher:
ISBN:
Category : DNA replication
Languages : en
Pages : 218
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Book Description
Here, I investigate the regulation of DNA replication during development in B. subtilis. I present evidence that replication is actively inhibited in response to the master regulator of sporulation, SpoOA. I further show that this regulation requires a gene transcribed in the presence of Spo0A, yneE, which I rename sirA, for s[barbelow]porulation i[barbelow]nhibitor of r[barbelow]eplication. The expression of sirA during growth, when it is not usually expressed, results in a growth defect and in the production of cells that lack genetic material. To investigate the mechanism by which sirA inhibits DNA replication, I performed a targeted screen to search for suppressors of sirA expression in the dnaA gene. Four mutations in three amino acids of DnaA allow cells to grow in the presence of SirA. I demonstrate that these residues, which form a patch on the surface of the N-terminal domain of DnaA, make up the interaction site between the DnaA and SirA proteins. Finally, I show that SirA interferes with DnaA's ability to bind the origin of replication.
Author: Lilah Lillian Rahn-Lee
Publisher:
ISBN:
Category : DNA replication
Languages : en
Pages : 218
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Book Description
Here, I investigate the regulation of DNA replication during development in B. subtilis. I present evidence that replication is actively inhibited in response to the master regulator of sporulation, SpoOA. I further show that this regulation requires a gene transcribed in the presence of Spo0A, yneE, which I rename sirA, for s[barbelow]porulation i[barbelow]nhibitor of r[barbelow]eplication. The expression of sirA during growth, when it is not usually expressed, results in a growth defect and in the production of cells that lack genetic material. To investigate the mechanism by which sirA inhibits DNA replication, I performed a targeted screen to search for suppressors of sirA expression in the dnaA gene. Four mutations in three amino acids of DnaA allow cells to grow in the presence of SirA. I demonstrate that these residues, which form a patch on the surface of the N-terminal domain of DnaA, make up the interaction site between the DnaA and SirA proteins. Finally, I show that SirA interferes with DnaA's ability to bind the origin of replication.
Author: Jan Löwe
Publisher: Springer
ISBN: 331953047X
Category : Science
Languages : en
Pages : 457
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Book Description
This book describes the structures and functions of active protein filaments, found in bacteria and archaea, and now known to perform crucial roles in cell division and intra-cellular motility, as well as being essential for controlling cell shape and growth. These roles are possible because the cytoskeletal and cytomotive filaments provide long range order from small subunits. Studies of these filaments are therefore of central importance to understanding prokaryotic cell biology. The wide variation in subunit and polymer structure and its relationship with the range of functions also provide important insights into cell evolution, including the emergence of eukaryotic cells. Individual chapters, written by leading researchers, review the great advances made in the past 20-25 years, and still ongoing, to discover the architectures, dynamics and roles of filaments found in relevant model organisms. Others describe one of the families of dynamic filaments found in many species. The most common types of filament are deeply related to eukaryotic cytoskeletal proteins, notably actin and tubulin that polymerise and depolymerise under the control of nucleotide hydrolysis. Related systems are found to perform a variety of roles, depending on the organisms. Surprisingly, prokaryotes all lack the molecular motors associated with eukaryotic F-actin and microtubules. Archaea, but not bacteria, also have active filaments related to the eukaryotic ESCRT system. Non-dynamic fibres, including intermediate filament-like structures, are known to occur in some bacteria.. Details of known filament structures are discussed and related to what has been established about their molecular mechanisms, including current controversies. The final chapter covers the use of some of these dynamic filaments in Systems Biology research. The level of information in all chapters is suitable both for active researchers and for advanced students in courses involving bacterial or archaeal physiology, molecular microbiology, structural cell biology, molecular motility or evolution. Chapter 3 of this book is open access under a CC BY 4.0 license.
Author: Monika Glinkowska
Publisher: Springer
ISBN: 3319105337
Category : Science
Languages : en
Pages : 56
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Book Description
This work describes the current knowledge of biochemical mechanisms regulating initiation of DNA replication in Escherichia coli, which focuses on the control of activity of the DnaA protein. Examples of direct linkages between DNA replication and other cellular processes are provided. In addition, similarities of the mechanisms of regulation of DNA replication operating in prokaryotic and eukaryotic cells are identified, and implications for understanding more complex processes, like carcinogenesis are suggested. Studies of recent years provided evidence that regulation of DNA replication in bacteria is more complex than previously anticipated. Multiple layers of control seem to ensure coordination of this process with the increase of cellular mass and the division cycle. Metabolic processes and membrane composition may serve as points where integration of genome replication with growth conditions occurs. It is also likely that coupling of DNA synthesis with cellular metabolism may involve interactions of replication proteins with other macromolecular complexes, responsible for various cellular processes. Thus, the exact set of factors participating in triggering the replication initiation may differ depending on growth conditions. Therefore, understanding the regulation of DNA duplication requires placing this process in the context of the current knowledge on bacterial metabolism, as well as cellular and chromosomal structure. Moreover, in both Escherichia coli and eukaryotic cells, replication initiator proteins were shown to play other roles in addition to driving the assembly of replication complexes, which constitutes another, yet not sufficiently understood, layer of coordinating DNA replication with the cell cycle.
Author: Akira Ishihama
Publisher: Springer
ISBN:
Category : Science
Languages : en
Pages : 284
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Book Description
In a series of sophisticated reviews a summary is created of our up-to-date knowledge of the molecular mechanisms which are underlying the control of cell growth and division both in prokaryotes and eukaryotes. Particularly focussed upon is chromosome replication and partitioning, cell division and cell cycling, and global gene expression.
Author: A.T. Ganesan
Publisher: Elsevier
ISBN: 0323138713
Category : Nature
Languages : en
Pages : 444
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Book Description
Genetics and Biotechnology of Bacilli, Volume 2 is a collection of papers from the "Fourth International Conference on Bacilli" held in California on June 21-24, 1987. One paper reviews the results of cloning and characterization of genes for secreted enzyme and of genes that control the expression of secreted enzymes in relation with other prokaryotic regulatory systems. Other papers tackle the regulation of gene expression during sporulation, the sigma factors, bacterial toxins, and antibiotic resistance genes. One paper reports that three genes responsible for the code for peptides found in BT cuboidal crystals have been successfully cloned. The three codes have different toxic characteristics in relation to tobacco hornworm larvae or mosquito larvae. Other papers examine replication. Such examination pertains to the two levels of control on the chromosome involved in DNA replication, or to the possible functional importance that several membranes associated DNA subcomplexes can have in Bacillus subtilis, where one of these appear to control initiation. Other papers discus secretion and extracellular enzymes, as well as, the different genetic systems and methods. This collection can prove beneficial for biochemists, micro-biologists, cellular researchers, and academicians involved in the study of cellular biology, microchemistry, or toxicology.
Author: Alexi I. Goranov
Publisher:
ISBN:
Category :
Languages : en
Pages : 446
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Book Description
(Cont.) My results demonstrate that the conserved recombination protein, RecA, mediates most of the transcriptional response under the tested conditions. More than 75% of the RecA-mediated transcriptional response is due to the expression of phage and mobile element genes and their indirect effects. Under conditions of replication elongation arrest, there is still a significant recA-independent response, at least part of which is mediated by the replication protein DnaA. The DnaA-mediated response appears to be conserved in other bacteria, as homologues if the affected genes also have DnaA binding sites in their promoter regions. Previously, one of the DnaA regulated genes, sda, has been shown to affect cell viability after perturbations in replication. Here I showed that another DnaA-regulated gene, ftsL, also affects cell survival after replication arrest by coordinating replication and cell-division. I believe that my results have furthered our understanding of how replication is coordinated with other cell-cycle processes, and have raised interesting questions for future investigation.
Author: Ariana Nakta Samadpour
Publisher:
ISBN:
Category :
Languages : en
Pages : 109
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Book Description
All organisms must control the timing of DNA replication to maintain their genomic stability. In bacteria, this is achieved through tightly controlling the frequency of replication initiation. Though it is well established that DNA topology is important for replication initiation, it was unclear whether the enzymes that modulate supercoiling are important for regulating this process. The work presented in this dissertation identifies a novel role for the essential topoisomerase, DNA gyrase, as a negative regulator of the replication initiator, DnaA. We find that gyrase activity is required for proper binding of DnaA to oriC and controls replication initiation frequency in the model Gram-positive bacterium, Bacillus subtilis. Based on the conservation of both gyrase and DnaA across all bacteria, and the importance of DNA topology for all stages of DNA replication, it is unlikely that this regulatory mechanism is unique to B. subtilis, and likely reflects a general strategy widely utilized by prokaryotes. Creating genetic variability within bacterial populations is important for adaptation and survival. Therefore, cells must balance the need for high fidelity DNA replication with the need for genetic variability. They promote fidelity by accurately copying their DNA and repairing damaged DNA. Cells can increase variability by inducing pathways that introduce mutations. In particular, genome architecture and transcription levels together dictate mutation rates as a result of collisions between DNA replication forks and RNA polymerase. In support of previous work, I found that transcription-coupled nucleotide excision repair facilitates the increased mutation rates of highly transcribed genes in B. subtilis. Furthermore, I found that this mutagenesis is dependent on the activity of DNA polymerase I and the translesion synthesis polymerases YqjH and YqjW. My work contributes to our understanding of transcription-associated mutagenesis.
Author: A. L. Sonenshein
Publisher:
ISBN:
Category : Bacillus subtilis
Languages : en
Pages : 664
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Book Description
Focusing on issues of gene organization, regulation, and evolution in the context of the whole life of the cell, this new volume complements the editors' classic 1993 volume Bacillus subtilis and Other Gram-Positive Bacteria. Building upon the previous edition, Bacillus subtilis and Its Closest Relatives contains an updated annotation of the complete B. subtilis genome and includes a unique compilation of major pathways of metabolism and macromolecular synthesis, correlating genes and proteins and assigning new functions to many genes. It also provides clear explanations of the major regulatory mechanisms that are unique to gram-positive bacteria as well as an overview of their special properties. This essential reference offers detailed, current information and is valuable reading for microbiologists, biotechnologists, and students.
Author: Rok Lenarcic
Publisher:
ISBN:
Category :
Languages : en
Pages : 203
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Book Description
Author: Tránsito García García
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Upon environmental or nutritional changes, bacteria must adjust their cell cycle with their growth rate. Most particularly, DNA replication initiation events must be controlled and coordinated with cell physiology to ensure faithful chromosome inheritance. In Bacillus subtilis, a model of Gram-positive bacteria, YabA plays a major role in down regulating initiation replication through interaction with the initiator protein DnaA and the clamp polymerase DnaN. However, YabA is a structural hub protein able to interact with other protein partners, indicating it might be multifunctional. Through its unique overall tri-dimentional structure composed of N-terminal four helix-bundle tetramer connected to four monomeric C-terminal domains by a highly flexible linker, YabA is capable to physically interact with more than one protein at a time, thus providing a suitable platform to integrate intracellular signals to replication initiation. Phosphorylation is the most prevalent post translational modification that modulates protein activities in response to cellular signals. Using in vitro phosphorylation and mass spectrometry we demonstrated that YabA is phosphorylated by the Hanks-type serine/threonine kinase YabT at a threonine residue localized within the flexible inter-domain region. YabT is a kinase activated by DNA and up-regulated during glucose starvation, sporulation and stationary phase. We constructed YabA phosphomimetic (yab-AT71D) and non-phosohorylatable (yabA-T71A) mutants to (i) confirm the requirement of T71 for YabT-mediated phosphorylation in vitro and (ii) perform in vivo and in vitro functional studies.We show in vivo that the phosphorylation of YabA is not involved in initiation control, but rather modulates bacillus developmental processes. We found that YabA phosphorylation inversely regulates sporulation and biofilm formation highlighting the multifunctional role of YabA as well as its role in integrating physiological signals to connect chromosomal replication initiation control with cell development. Our results support a role of YabT-mediated phosphorylation of YabA in Bacillus subtilis life-style decision making through the modulation of Spo0A-P intracellular levels. We established that YabA phosphorylation correlates with high cellular levels of Spo0A-P, leading to sporulation stimulation and preventing biofilm formation. Additionally, thin layer chromatography (TLC) analysis and In-Gel assays showed that YabA possess an atypical "ATP / GTPase" activity. This unusual activity seems to be modulated by phosphorylation of the YabA T71 residue. Our functional analysis pointed to a potential role of YabA in the c-di-GMP signaling transduction pathway, known to regulate biofilm formation in many bacteria. This suggesting a complex regulatory role of YabA during development, involving signaling crosstalk. LC-MS analyzes showed that when overexpressed in Escherichia coli, YabA is phosphorylated on the residue Y90 in a YabT independent manner. Y90 belongs to the interaction C-terminal domain, which contacts DnaA and DnaN. We found that Y90 was involved YabA-mediated replication initiation control. We provided evidence that phosphorylation state of YabA at Y90 can potentially modulates a protein-interaction switch with its protein partners DnaA and DnaN in a yeast-two-hybrid-based assay. Although we did not identified a kinase responsible for the phosphorylation of YabA at Y90 in B. subtilis, this finding hint at the possibility of a YabA-mediated control of initiation modulated by phosphorylation in this bacteria. Thus, all of these in vitro and in vivo observations suggest the existence of different modes of regulation of YabA activity by phosphorylation, involving threonine and tyrosine residues. This study established that YabA, apart from its role during replication initiation, plays a key regulatory role in B. subtilis development.
