Project description:Staphylococcus aureus is one of the most common hospital acquired infections. It colonizes immunocompromised patients and with the number of antibiotic resistant strains increasing, medicine needs new treatment options. Understanding more about the proteins this organism uses would further this goal. Hypothetical proteins are sequences thought to encode a functional protein but for which little to no evidence of that function exists. About half of the genomic proteins in reference strain S. aureus NCTC 8325 are hypothetical. Since annotation of these proteins can lead to new therapeutic targets, a high demand to characterize hypothetical proteins is present. This work examines 35 hypothetical proteins from the chromosome of S. aureus NCTC 8325. Examination includes physiochemical characterization; sequence homology; structural homology; domain recognition; structure modeling; active site depiction; predicted protein-protein interactions; protein-chemical interactions; protein localization; protein stability; and protein solubility. The examination revealed some hypothetical proteins related to virulent domains and protein-protein interactions including superoxide dismutase, O-antigen, bacterial ferric iron reductase and siderophore synthesis. Yet other hypothetical proteins appear to be metabolic or transport proteins including ABC transporters, major facilitator superfamily, S-adenosylmethionine decarboxylase, and GTPases. Progress evaluating some hypothetical proteins, particularly the smaller ones, was incomplete due to limited homology and structural information in public repositories. These data characterizing hypothetical proteins will contribute to the scientific understanding of S. aureus by identifying potential drug targets and aiding in future drug discovery.
Project description:Staphylococcus aureus is a gram-positive cocci and an important human commensal bacteria and pathogen. S. aureus infections are increasingly difficult to treat because of the emergence of highly resistant MRSA (Methicillin-resistant S. aureus) strains. Here we present a method to study differential gene expression in S. aureus using high-throughput RNA-sequencing (RNA-seq). We use RNA-seq to examine the differential gene expression in S. aureus RN4220 cells containing an exogenously expressed transcription factor and between two S. aureus strains (RN4220 and NCTC8325-4). The information provided by RNA-seq was a significant advance over previously described microarray based techniques. We investigated the sequence and gene expression differences between RN4220 and NCTC8325-4 and used the RNA-seq data to identify S. aureus promoters suitable for in vitro analysis. We used RNA-seq to describe, on a genome wide scale, genes positively and negatively regulated by a phage encoded transcription factor, gp67. RNA-seq offers the ability to study differential gene expression with single-nucleotide resolution, and is a considerable improvement over the predominant genome-wide transcriptome technologies used in S. aureus.
Project description:To analyze function of three Two-component systems SAOUHSC_00184-185, SAOUHSC_01313-1314, and SAOUHSC_01980-1981, we have employed whole genome microarray expression profiling to identify genes transcription changed in respective mutant strains. Target TCSs were replaced by ermB gene. Cells were grown to OD600=2.0, and the RNA level of wild type NCTC8325 and three TCSs mutant were compared.
Project description:Staphylococcus aureus is a gram-positive cocci and an important human commensal bacteria and pathogen. S. aureus infections are increasingly difficult to treat because of the emergence of highly resistant MRSA (Methicillin-resistant S. aureus) strains. Here we present a method to study differential gene expression in S. aureus using high-throughput RNA-sequencing (RNA-seq). We use RNA-seq to examine the differential gene expression in S. aureus RN4220 cells containing an exogenously expressed transcription factor and between two S. aureus strains (RN4220 and NCTC8325-4). The information provided by RNA-seq was a significant advance over previously described microarray based techniques. We investigated the sequence and gene expression differences between RN4220 and NCTC8325-4 and used the RNA-seq data to identify S. aureus promoters suitable for in vitro analysis. We used RNA-seq to describe, on a genome wide scale, genes positively and negatively regulated by a phage encoded transcription factor, gp67. RNA-seq offers the ability to study differential gene expression with single-nucleotide resolution, and is a considerable improvement over the predominant genome-wide transcriptome technologies used in S. aureus. RNA-seq analysis of Staphylococcus aureus RN4220 (electrocompetent strain) carrying either empty pRMC2 (inducible expression vector) or pRMC2 carrying the ORF67 gene (encodes gp67). Both strains were grown to OD 0.2 and transgene expression was induced with 100ng/ml anhydrotetracycline. As a control, Staphylococcus aureus strain NCTC8325-4 (non-electrocompetent strain) was grown under identical conditions except without the addition of anhydrotetracycline.