Molecular Biology Commons^™

Profiling The Circulating Mrna Transcriptome In Human Liver Disease, Aejaz Sayeed, Brielle E Dalvano, David E Kaplan, Usha Viswanathan, John Kulp, Alhaji H Janneh, Lu-Yu Hwang, Adam Ertel, Cataldo Doria, Timothy Block

Department of Cancer Biology Faculty Papers

The human circulation contains cell-free DNA and non-coding microRNA (miRNA). Less is known about the presence of messenger RNA (mRNA). This report profiles the human circulating mRNA transcriptome in people with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) to determine whether mRNA analytes can be used as biomarkers of liver disease. Using RNAseq and RT-qPCR, we investigate circulating mRNA in plasma from HCC and LC patients and demonstrate detection of transcripts representing more than 19,000 different protein coding genes. Remarkably, the circulating mRNA expression levels were similar from person to person over the 21 individuals whose samples were analyzed by …

Methylation Of Salmonella Typhimurium Flagella Promotes Bacterial Adhesion And Host Cell Invasion, Julia A Horstmann, Michele Lunelli, Hélène Cazzola, Johannes Heidemann, Caroline Kühne, Pascal Steffen, Sandra Szefs, Claire Rossi, Ravi K Lokareddy, Chu Wang, Laurine Lemaire, Kelly T Hughes, Charlotte Uetrecht, Hartmut Schlüter, Guntram A Grassl, Theresia E B Stradal, Yannick Rossez, Michael Kolbe, Marc Erhardt

Department of Biochemistry and Molecular Biology Faculty Papers

The long external filament of bacterial flagella is composed of several thousand copies of a single protein, flagellin. Here, we explore the role played by lysine methylation of flagellin in Salmonella, which requires the methylase FliB. We show that both flagellins of Salmonella enterica serovar Typhimurium, FliC and FljB, are methylated at surface-exposed lysine residues by FliB. A Salmonella Typhimurium mutant deficient in flagellin methylation is outcompeted for gut colonization in a gastroenteritis mouse model, and methylation of flagellin promotes bacterial invasion of epithelial cells in vitro. Lysine methylation increases the surface hydrophobicity of flagellin, and enhances flagella-dependent adhesion of …

Methylation Of Salmonella Typhimurium Flagella Promotes Bacterial Adhesion And Host Cell Invasion., Julia A Horstmann, Michele Lunelli, Hélène Cazzola, Johannes Heidemann, Caroline Kühne, Pascal Steffen, Sandra Szefs, Claire Rossi, Ravi K Lokareddy, Chu Wang, Laurine Lemaire, Kelly T Hughes, Charlotte Uetrecht, Hartmut Schlüter, Guntram A Grassl, Theresia E B Stradal, Yannick Rossez, Michael Kolbe, Marc Erhardt

Department of Biochemistry and Molecular Biology Faculty Papers

The long external filament of bacterial flagella is composed of several thousand copies of a single protein, flagellin. Here, we explore the role played by lysine methylation of flagellin in Salmonella, which requires the methylase FliB. We show that both flagellins of Salmonella enterica serovar Typhimurium, FliC and FljB, are methylated at surface-exposed lysine residues by FliB. A Salmonella Typhimurium mutant deficient in flagellin methylation is outcompeted for gut colonization in a gastroenteritis mouse model, and methylation of flagellin promotes bacterial invasion of epithelial cells in vitro. Lysine methylation increases the surface hydrophobicity of flagellin, and enhances flagella-dependent adhesion of …

How To Untie A Protein Knot., Sitao Yin, Brittiny Dhital, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

The origin of protein backbone threading through a topological knot remains elusive. To understand the evolutionary origin of protein knots, in this issue of StructureKo et al. (2019) used circular permutation to untie a knotted protein. They showed that a domain-swapped dimer releases the knot and the associated high-energy state for substrate binding.

Using Competition Assays To Quantitatively Model Cooperative Binding By Transcription Factors And Other Ligands., Jacob Peacock, James B Jaynes

Department of Biochemistry and Molecular Biology Faculty Papers

BACKGROUND: The affinities of DNA binding proteins for target sites can be used to model the regulation of gene expression. These proteins can bind to DNA cooperatively, strongly impacting their affinity and specificity. However, current methods for measuring cooperativity do not provide the means to accurately predict binding behavior over a wide range of concentrations.

METHODS: We use standard computational and mathematical methods, and develop novel methods as described in Results.

RESULTS: We explore some complexities of cooperative binding, and develop an improved method for relating in vitro measurements to in vivo function, based on ternary complex formation. We derive …

Decorin As A Multivalent Therapeutic Agent Against Cancer., Thomas Neill, Liliana Schaefer, Renato V. Iozzo

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Decorin is a prototypical small leucine-rich proteoglycan that epitomizes the multifunctional nature of this critical gene family. Soluble decorin engages multiple receptor tyrosine kinases within the target-rich environment of the tumor stroma and tumor parenchyma. Upon receptor binding, decorin initiates signaling pathways within endothelial cells downstream of VEGFR2 that ultimately culminate in a Peg3/Beclin 1/LC3-dependent autophagic program. Concomitant with autophagic induction, decorin blunts capillary morphogenesis and endothelial cell migration, thereby significantly compromising tumor angiogenesis. In parallel within the tumor proper, decorin binds multiple RTKs with high affinity, including Met, for a multitude of oncosuppressive functions including growth inhibition, tumor cell …

Mechanism Of N-Methylation By The Trna M1g37 Methyltransferase Trm5., Thomas Christian, Georges Lahoud, Cuiping Liu, Katherine Hoffmann, John J Perona, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Trm5 is a eukaryal and archaeal tRNA methyltransferase that catalyzes methyl transfer from S-adenosylmethionine (AdoMet) to the N(1) position of G37 directly 3' to the anticodon. While the biological role of m(1)G37 in enhancing translational fidelity is well established, the catalytic mechanism of Trm5 has remained obscure. To address the mechanism of Trm5 and more broadly the mechanism of N-methylation to nucleobases, we examined the pH-activity profile of an archaeal Trm5 enzyme, and performed structure-guided mutational analysis. The data reveal a marked dependence of enzyme-catalyzed methyl transfer on hydrogen ion equilibria: the single-turnover rate constant for methylation increases by one …

Characterizing The Dynamics And Functional Role Of Site-Specific Phosphorylation Of G Protein-Coupled Receptors, John M. Busillo

Full-Text Theses & Dissertations

Phosphorylation of G protein-coupled receptors (GPCRs) by GPCR kinases (GRKs) and the subsequent recruitment of arrestin is a well-established paradigm that initiates the process known as desensitization. However, an emerging theme in GPCR regulation is the possibility of differential regulation dictated by the phosphorylation pattern elicited by the different members of the GRK family. Therefore, we have used small interfering RNA-mediated knock down of the GRKs and arrestins in an attempt to better understand how phosphorylation regulates the activity and signaling of the M3 muscarinic acetylcholine receptor (M3 mAChR) and CXCR4, two receptors endogenously expressed in HEK293 cells.

Using a …

Role Of Immunodominant T Cell Responses To Minor Histocompatibility Antigens In A Mouse Model Of Graft-Versus-Host Disease, Marc Adam Berger, B.S. Thomas Jefferson University

Full-Text Theses & Dissertations

Graft-versus-host-disease (GVHD) is a major complication of major histocompatibility complex (MHC) matched bone marrow transplantation. GVHD is the result of an immune-mediated attack, by T lymphocytes derived from donor bone marrow, against recipient tissues expressing minor histocompatibility antigen (miHA) differences. There is a lack of knowledge concerning the nature of in vivo immune responses to miHA during GVHD. C57BL/6By (B6/By) and BALB.B mouse strains both express the H-2B MHC haplotype but differ at more than 40 miHA loci. Both the in vitro and in vivo T cell responses to miHA expressed by BALB.B and CXB recombinant inbred (RI) strains of …