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Full-Text Articles in Molecular Biology

Trna Anticodon Cleavage By Target-Activated Crispr-Cas13a Effector, Ishita Jain, Matvey Kolesnik, Konstantin Kuznedelov, Leonid Minakhin, Natalia Morozova, Anna Shiriaeva, Alexandr Kirillov, Sofia Medvedeva, Alexei Livenskyi, Laura Kazieva, Kira S Makarova, Eugene V Koonin, Sergei Borukhov, Konstantin Severinov, Ekaterina Semenova Apr 2024

Trna Anticodon Cleavage By Target-Activated Crispr-Cas13a Effector, Ishita Jain, Matvey Kolesnik, Konstantin Kuznedelov, Leonid Minakhin, Natalia Morozova, Anna Shiriaeva, Alexandr Kirillov, Sofia Medvedeva, Alexei Livenskyi, Laura Kazieva, Kira S Makarova, Eugene V Koonin, Sergei Borukhov, Konstantin Severinov, Ekaterina Semenova

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Type VI CRISPR-Cas systems are among the few CRISPR varieties that target exclusively RNA. The CRISPR RNA–guided, sequence-specific binding of target RNAs, such as phage transcripts, activates the type VI effector, Cas13. Once activated, Cas13 causes collateral RNA cleavage, which induces bacterial cell dormancy, thus protecting the host population from the phage spread. We show here that the principal form of collateral RNA degradation elicited by Leptotrichia shahii Cas13a expressed in Escherichia coli cells is the cleavage of anticodons in a subset of transfer RNAs (tRNAs) with uridine-rich anticodons. This tRNA cleavage is accompanied by inhibition of protein synthesis, thus …


Qualitative Proteomic And Genomic Analysis Of Klebsiella Pneumoniae Bacteriophage Kaomega, Emilee Carr Aug 2022

Qualitative Proteomic And Genomic Analysis Of Klebsiella Pneumoniae Bacteriophage Kaomega, Emilee Carr

Undergraduate Honors Theses

Klebsiella pneumoniae is a Gram-negative Enterobacteriaceae that is a common nosocomial pathogen causing pneumonia, infections in the bloodstream, wound infections, and meningitis. It has developed natural resistance to multiple antibiotics, most notably carbapenems which are often seen as the last line of defense against multi-drug resistant pathogens. Bacteriophages are being investigated as a promising alternative treatment to antibiotics in fighting these resistant pathogens. KaOmega, a Klebsiella pneumoniae bacteriophage, was isolated, sequenced, and annotated to characterize and understand its potential for use in a phage therapy. Characterization included Phyre2 analysis to predict putative protein functions based on structural homology, burst size …


Premature Rho-Dependent Transcription Termination In Escherichia Coli : Link To Translation And Gene Regulation, Gabriele Baniulyte Jan 2019

Premature Rho-Dependent Transcription Termination In Escherichia Coli : Link To Translation And Gene Regulation, Gabriele Baniulyte

Legacy Theses & Dissertations (2009 - 2024)

Transcription termination factor Rho is an essential protein in Escherichia coli and related bacteria. The primary function of Rho is to clear unproductive RNA polymerases from the DNA template to minimize negative effects associated with uncontrolled transcription. Although most of the Rho termination events are constitutive, premature Rho-mediated termination was observed at 3% of all affected transcripts indicating active regulation of Rho activity. In this work, we investigated the regulatory mechanism behind premature Rho-dependent transcription termination in two unrelated genes: suhB and topAI. We show that in both cases transcription is terminated inside the coding gene as a consequence of …


Post-Translational Modifications And Functional Studies Of Dksa In Escherichia Coli, Andrew Charles Isidoridy Jan 2019

Post-Translational Modifications And Functional Studies Of Dksa In Escherichia Coli, Andrew Charles Isidoridy

Legacy Theses & Dissertations (2009 - 2024)

DksA is a bacterial gene regulator that functions synergistically with the stress alarmone ppGpp to mediate the stringent response. DksA also functions independently of ppGpp to regulate transcription of a number of genes. DksA function is dependent on its binding affinity to RNA polymerase and requires specific interactions between RNAP and catalytic amino acids located on the coiled coil tip, D74 and A76. While much of the previous work on DksA has focused on understanding the mechanisms of action and the numerous gene targets for transcriptional regulation, little is known about the mechanisms by which DksA expression and function may …


Transcriptional Regulation Of Dksa In E. Coli, Daniel Thomas Woods Jan 2019

Transcriptional Regulation Of Dksa In E. Coli, Daniel Thomas Woods

Legacy Theses & Dissertations (2009 - 2024)

DksA is a global transcription factor that binds RNAP directly to regulate the expression of many genes and operons, including ribosomal RNA, in a ppGpp-dependent or ppGpp–independent manner. It is also involved in facilitating the process of DNA replication by removing stalled transcription elongation complexes that could block the progress of the replication fork. In addition, DksA is important for colonization, establishment of biofilms, and pathogenesis. In order to sustain these various functions, an adequate level of cellular DksA is required. This work tested the hypothesis that the E. coli dksA is substantially regulated at the level of transcription. Using …


The Structural And Folding Characteristics Of The Plasmid-Encoded Toxin From Enteroaggregative Escherichia Coli, Patricia Scaglione Jan 2008

The Structural And Folding Characteristics Of The Plasmid-Encoded Toxin From Enteroaggregative Escherichia Coli, Patricia Scaglione

Electronic Theses and Dissertations

Plasmid-encoded toxin (Pet) from enteroaggregative Escherichia coli is a member of the autotransporter subfamily termed SPATE (serine protease autotransporters of Enterobacteriaceae). Autotransporters, which are the most common Gram-negative secreted virulence factors, contain three functional domains: an amino terminal leader sequence, a mature protein or passenger domain, and a carboxy-terminal β domain. The leader sequence targets the protein to the periplasmic space and the β domain then forms a β-barrel pore in the outer membrane of the bacterium which allows the passenger domain to enter the external milieu. In some cases the passenger domain is cleaved from the β-barrel at the …


Construction Of An Escherichia Coli Lac Repressor-Based System To Study Human Cytomegalovirus Gene Expression, Laura Fernanda Cageao-Luchetti Jan 1999

Construction Of An Escherichia Coli Lac Repressor-Based System To Study Human Cytomegalovirus Gene Expression, Laura Fernanda Cageao-Luchetti

Theses and Dissertations in Biomedical Sciences

An Escherichia coli lac repressor-based system was developed to study the roles of human cytomegalovirus (HCMV) genes during viral replication. To this end, a recombinant HCMV expressing the lac repressor was generated (RVlac), and an HCMV-specific promoter was targeted for conditional expression by inserting the lac operator sequence. The promoter of a nonessential gene was chosen in order to be able to assess parameters of repression and derepression of the operator-containing promoter in the endogenous locus, without having virus growth dependent on the specific inducer isopropylthiogalactoside (IPTG). The feasibility of this approach to conditionally express an HCMV promoter …