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PubMed2025

RNA/DNA Binding Protein TDP43 Regulates DNA Mismatch Repair Genes with Implications for Genome Stability.

TDP43 is an RNA/DNA binding protein increasingly recognized for its role in neurodegenerative conditions, including amyotrophic lateral sclerosis and frontotemporal dementia (FTD). As characterized by its aberrant nuclear export and cytoplasmic aggregation, TDP43 proteinopathy is a hallmark feature in over 95% of ALS/FTD cases, leading to the formation of detrimental cytosolic aggregates and a reduction in nuclear functionality within neurons. Building on our prior work linking TDP43 proteinopathy to the accumulation of DNA double-strand breaks (DSBs) in neurons, the present investigation uncovers a novel regulatory relationship between TDP43 and DNA mismatch repair (MMR) gene expressions. Here, we show that TDP43 depletion or overexpression directly affects the expression of key MMR genes. Alterations include MLH1, MSH2, MSH3, MSH6, and PMS2 levels across various primary cell lines, independent of their proliferative status. Our results specifically establish that TDP43 selectively influences the expression of MLH1 and MSH6 by influencing their alternative transcript splicing patterns and stability. We furthermore find aberrant MMR gene expression is linked to TDP43 proteinopathy in two distinct ALS mouse models and post-mortem brain and spinal cord tissues of ALS patients. Notably, MMR depletion resulted in the partial rescue of TDP43 proteinopathy-induced DNA damage and signaling. Moreover, bioinformatics analysis of the TCGA cancer database reveals significant associations between TDP43 expression, MMR gene expression, and mutational burden across multiple cancers. Collectively, our findings implicate TDP43 as a critical regulator of the MMR pathway and unveil its broad impact on the etiology of both neurodegenerative and neoplastic pathologies.

Amyotrophic lateral sclerosis↗

PubMed2026

A plasmid-associated immunoglobulin-binding protein in Acinetobacter baumannii.

BACKGROUND: Acinetobacter baumannii is a critical global health threat due to multidrug resistance and high mortality. Although antimicrobial resistance mechanisms are well characterised, the virulence determinants that drive severe infections remain poorly understood. METHODS: We screened 89 carbapenem-resistant clinical isolates of A. baumannii for virulence in animal infection models and combined comparative genomics with functional assays to identify virulence factors. An immunoglobulin-binding protein from A. baumannii (ImbA) encoded on the type D plasmid was selected and characterised. Protein-immunoglobulin interactions were analysed by pull-down and biolayer interferometry. Additional ImbA inhibition of IgG-Fcγ receptor binding by flow cytometry were tested. Protective efficacy was evaluated in mice using vaccination or anti-ImbA antibodies. FINDINGS: A type D plasmid was consistently linked to high virulence in clinical isolates. The deletion of plasmid-encoded ImbA attenuated virulence. ImbA bound murine IgA and IgG with high affinity. The binding to the Fc region of IgG disrupted IgG-Fcγ receptor interactions. Vaccination with recombinant ImbA improved survival and reduced bacterial dissemination in female mice with anti-ImbA antibodies partially protecting against lethal infection. Bacterial burdens in the blood were reduced in treated groups. INTERPRETATION: Our study demonstrates ImbA as an unrecognised plasmid-encoded virulence factor in A. baumannii. By intercepting host immunoglobulins, ImbA drives immune evasion and hypervirulence. Blocking ImbA by vaccination and antibody therapy restored host defence and improved outcomes in female mice, highlighting ImbA as a non-antibiotic therapeutic target with potential against multidrug-resistant A. baumannii. FUNDING: Bio&Medical Technology Development Program of the National Research Foundation (NRF), funded by the Korean government (MSIT) (No. RS-2023-00219213); Korea Research Institute of Bioscience and Biotechnology (KRIBB) Research Initiative Program.

Animals↗

PubMed2026

Chromatin-binding protein HMGN1 promotes HCC tumorigenesis via histone methylation-induced RALB transcriptional suppression.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide, with metastasis being the primary cause of its high mortality. The chromatin-binding protein, high mobility group nucleosome binding domain 1 (HMGN1), has been implicated in tumour progression, but its specific role and mechanism in HCC metastasis remain unclear. This study investigates the function of HMGN1 and its potential as a therapeutic target. Analysis of patient samples confirms an upregulation of HMGN1 in HCC tissues, correlating with advanced disease and poor prognosis. Functional assays demonstrate that HMGN1 promotes HCC metastasis in vitro and in vivo. Mechanistically, integrated RNA sequencing and chromatin immunoprecipitation sequencing analyses reveal that HMGN1 binds to the promoter of RAS-like proto-oncogene B (RALB) gene, recruiting the repressive histone mark H3K9me2 to epigenetically silence its transcription and drive metastasis. Therapeutically, a nanoparticle delivery system for siRNA against HMGN1 effectively silences its expression and inhibits metastasis in orthotopic liver xenograft tumour models. Our findings establish HMGN1 as a key epigenetic driver of HCC metastasis and highlight siRNA-nanoparticle targeting of HMGN1 as a promising precision therapeutic strategy.

Humans↗

PubMed2026

Genome-wide identification of olfactory receptor and odorant-binding protein gene families and their roles in Heliothine chemosensory evolution.

Chemosensory systems play key roles in the survival and reproductive success of insects. Two large and diverse chemosensory gene families, odorant receptors (ORs) and odorant-binding proteins (OBPs), play critical roles in insect chemosensation and mediate odour-guided behaviours. In the process of insect chemosensation, odorants from the environment pass through pores in the antennal sensilla and become soluble in the sensillar lymph, either directly on contact or by binding to an OBP. Solubilized odour molecules diffuse through the lymph until they reach and activate their cognate ORs, sending electrophysiological signals to the insect brain. To better understand the evolutionary roles of OR and OBP gene families among members of the Heliothinae, we systematically characterized these two gene families in Chloridea virescens (Lepidoptera: Noctuidae). A total of 81 ORs and 49 OBPs were identified genome-wide. Based on the number and positions of conserved cysteine residues, the OBPs were classified into three types: 34 Classic OBPs, 8 Minus-C OBPs and 7 Plus-C OBPs. Phylogenetic analyses identified potential gene duplications and losses within OR and OBP gene families among members of the Heliothinae, which may be associated with differences in their volatile sensation and olfactory behaviours. Further motif and structural analyses identified a conserved region that was unique among pheromone receptors and predicted as key residues of the binding pocket, implying its critical role in pheromone detection. Future work should focus on experimentally validating its function. Overall, our findings provide important insights into how chemosensory gene evolution contributes to ecological adaptation and reproductive isolation in the Heliothine moths.

Animals↗

PubMed2026

Evaluating detection of Histophilus somni immunoglobulin-binding protein A DR2 Fic: A species-specific gene target for recombinase polymerase amplification relative to long-read sequencing of respiratory samples from feedlot calves.

Histophilosis is an important cause of morbidity and mortality as well as antimicrobial use in feedlot cattle across North America. Detection of Histophilus somni by culture is challenging, and there is no standardized tool for distinguishing isolates that carry virulence factors most likely to contribute to disease. The DR2 repeat of H. somni-associated virulence factor 'immunoglobulin-binding protein A' (ibpA DR2) harbors a Fic domain that mediates host cell cytotoxicity and is essential for histophilosis. For rapid detection of ibpA DR2 in extracted DNA, we developed a real-time recombinase polymerase amplification (RPA) assay with a runtime of 24 min at 39 °C. DNA from H. somni-RPA-positive respiratory swabs (n = 73) was screened for ibpA DR2 using the novel RPA assay and long-read metagenomic sequencing, as well as nanopore whole-genome sequencing (WGS) of H. somni isolated from the same samples. IbpA DR2 was identified in 71% and 70% of tested samples using RPA and WGS, respectively, and in ≤41% of samples using metagenomic sequencing. The likelihood of detection by RPA did not differ (OR 1.1, 95% CI (0.42, 2.9), P > 0.99) from WGS; however, agreement between these assays was only fair (κ = 0.31). Conversely, RPA (OR 3.4, 95% CI (1.6, 8.2)) and WGS (OR 8.0, 95% CI (2.4, 42)) were more likely (P < 0.001) to detect ibpA DR2 than metagenomic sequencing, likely reflecting limited coverage of H. somni by metagenomics. This study demonstrated that RPA and long-read WGS detected ibpA DR2 with similar frequencies in extracted DNA and H. somni isolates, respectively. Further testing of non-target isolates confirmed the analytical specificity of ibpA DR2 to H. somni. Further investigation of the diagnostic validity for RPA-based ibpA DR2 detection is required in a larger cohort of field samples, as a rapid screening tool for H. somni most likely to contribute to disease.

Animals↗

PubMed2025

Chromatin Immunoprecipitation for Standard, Rare, or Weakly Binding Proteins.

Various proteins interact with specific genome regions, playing crucial roles in gene regulation. Chromatin Immunoprecipitation (ChIP) is the most commonly used method to study protein-DNA interactions in vivo. By combining ChIP with high-throughput sequencing, ChIP-seq allows for studying the genome-wide localization of proteins. Although several ChIP protocols are available for plant tissues, they are primarily designed for histone modifications and abundant proteins with high DNA-binding affinity, which are considered as the "standard targets." Here we describe a ChIP protocol for plant tissues not only optimized for the standard targets but also adapted for proteins with low abundances or weak DNA-binding ability. Successful execution of the protocol enables reliable generation of DNA templates for quantitative PCR or libraries for next-generation sequencing, which makes it an effective tool for analyzing genomic interactions of a wide range of proteins.

Chromatin Immunoprecipitation↗

PubMed2024

Analysis of different expression RNA binding protein genes in mouse microglia cell from the brains of mice 72 h after subarachnoid hemorrhage or sham operation.

BACKGROUND: The prognosis of brain injury caused by subarachnoid hemorrhage (SAH) is poor. Previous studies showed that abnormal function of RBPs might be involved in brain injury, neuroinflammation and further affect microglia homeostasis. However, no studies have systematically analyzed the genome-wide abnormal expression of RBPs genes in microglia during SAH. METHODS: RNA-seq data of microglia from the SAH mouse group (SAH) and control sham-operated mouse group (sham) were downloaded from the GEO database in GSE167957, including four samples from the sham group and four samples from the SAH group for subsequent analysis.Utilizing GO and KEGG functional enrichment analyses, we conducted a comprehensive study of differentially expressed genes (DEGs), alternative splicing patterns, and co-expression networks to gain deeper insights into the differential expression of RNA-binding proteins (RBPs) and differential alternative splicing events (ASEs) between the SAH (subarachnoid hemorrhage) and sham groups. This analysis aimed to elucidate the potential mechanisms underlying the aberrant expression of RBPs in microglia during brain injury caused by SAH. RESULTS: ASEs and co-expression analyses of differentially expressed RBPs and differential ASEs were carried out in microglia in terms of gene expression. GO and KEGG functional enrichment analysis showed that aberrantly expressed RBPs such as Mcm7, Mtdh, SRSF3, and Hnrnpa2b1 may affect and regulate downstream Csnk1d, Uckl1 and other protein phosphorylation-related genes by alterative splicing. CONCLUSION: RBPs were aberrantly expressed in microglia during the development of brain injury secondary to SAH, regulating alterative splicing of downstream genes and influencing the progression of SAH brain injury in this study. This implies that RBPs are important for the identification of new therapeutic targets for brain injury after SAH.

Animals↗

PubMed2026

The insulin-like growth factor 2 mRNA-binding protein 2 affects tumor cell metabolism via mitochondrial transporter activity and lipid alterations.

The insulin-like growth factor 2 mRNA-binding protein (IGF2BP) family is overexpressed in cancer and associated with poor prognosis. IGF2BP2 has been linked to single metabolic alterations by acting on its RNA targets. Here, we used a comprehensive approach to elucidate the effects of IGF2BP2 on primary and lipid metabolism. 13C-metabolic flux analysis (MFA) combined with RNA-Seq data revealed that IGF2BP2 affects mitochondrial fluxes by regulating the expression of several mitochondrial transporters, such as mitochondrial pyruvate carrier 1 (MPC1) and uncoupling protein 2 (UCP2). Methyl pyruvate reversed the gene expression patterns of UCP2 and CPT1A in HCT116 IGF2BP2 knockout (KO) cells by bypassing MPC1. Interestingly, an altered expression of the transporter UCP2 was also observed in a patient-derived tumor organoid (PDO), in which IGF2BP2 was knocked down. The altered glutamine metabolism seen in the 13C-MFA and the citrate label data derived from extracted mitochondria confirm a rerouting of glutamine almost exclusively into the mitochondria and a reduction of glycolytic carbon intake into the mitochondria. Due to changes in palmitate labeling patterns, lipid stainings were performed, suggesting lipid accumulation in KO cells. A lipidomic analysis revealed altered compositions across almost all lipid species. Further, lipogenic genes involved in fatty acid and cholesterol metabolism were differentially expressed. Most of the differentially expressed genes are potential direct targets of IGF2BP2 based on publicly available IGF2BP2 CLIP data. Overall, these results show the influence of IGF2BP2 on the central carbon metabolism of cancer cells, primarily through its effects on MPC1 and the resulting effects on UCP2. The complex interaction of IGF2BP2 with the metabolic network provides important insights into tumor metabolism, particularly relevant to tumor growth and resistance to therapy.

Journal Article↗

PubMed2026

Decoding sequence recognition code of nucleic acid-binding proteins of human-infecting DNA viruses.

Human-infecting DNA viruses remain major health threats, yet the DNA-recognition mechanisms of their nucleic acid-binding proteins (NBPs) are poorly understood. Here, we systematically profiled 103 viral NBPs from human-infecting DNA viruses, with three NBPs from non-human-infecting DNA viruses as controls, using high-throughput screening. This analysis identified diverse DNA-binding motifs and specificity modules, including convergent recognition of a conserved CCACC motif across phylogenetically distant viruses. Notably, viral NBP binding-site distributions varied with genome size, and several NBPs from small-genome viruses showed enrichment on mitochondrial DNA. Functional assays further supported their mitochondrial association and effects on mitochondrial membrane potential. By integrating an ivTRT-based ssDNA-SELEX workflow, we further found that ssDNA viral NBPs recognize dimer-like and inverted-repeat sequences with potential to form stem-loop structures. Collectively, this study constructs a comprehensive viral NBP DNA-recognition atlas, offering a fundamental resource for elucidating viral genome recognition mechanisms, virus-mitochondria interactions, and developing future antiviral strategies.

Letter↗

PubMed2025

Hexokinase 2 is an RNA-binding protein that regulates mRNA translation independently of glycolysis and induces melanoma cell proliferation.

Although metabolic benefits of glycolysis have been extensively described in tumor cells, the extra-metabolic functions linked to this energetic pathway in tumor growth and cell proliferation have not been clearly established yet. Recently, some key glycolytic enzymes, such as glyceraldehyde-3-phosphate dehydrogenase and pyruvate kinase 2, were reported to regulate mRNA translation. Translational control of gene expression is considered as a critical effector in cancer biology, representing a highly promising area of research. Here, we report that Hexokinase 2 (HK2), a glucose kinase that catalyzes the first step of glycolysis at the outer mitochondrial membrane (OMM), is an RNA-binding protein (RBP) that regulates mRNA translation in melanoma cell lines. Polysome profiling experiments followed by RNA sequencing indicate that the translational regulation exerted by HK2 is partly independent of the metabolic status or the glycolytic pathway. We found that HK2 specifically regulates translation of the mRNA encoding SOX10, a transcription factor implicated in the regulation of tumor initiation, maintenance, and progression in melanoma. RNA-protein interaction assays, including CrossLinking ImmunoPrecipitation (CLIP), indicate that HK2 is an RBP whose interaction with RNA is independent of its enzymatic activity, its ability to bind glucose or its association with the OMM. HK2 directly interacts with the 5' untranslated region (5'UTR) of the SOX10 mRNA through a stem-loop RNA secondary structure. Using RNA-protein proximity ligation assays and a fluorescence-based ribosome-bound mRNA mapping method, we found that high glucose conditions, which promote the release of HK2 from the OMM, induce an increase in HK2-SOX10 mRNA interaction and SOX10 mRNA translation in the cytoplasm. We further showed that HK2-dependent SOX10 mRNA translation is involved in melanoma cell proliferation and colony formation. Collectively, our data highlight a nonmetabolic function of HK2 acting as an RBP and translation regulator.

Hexokinase↗

PubMed2024

Deficiency of IL-22-binding protein enhances the ability of the gut microbiota to protect against enteric pathogens.

Interleukin 22 (IL-22) promotes intestinal barrier integrity, stimulating epithelial cells to enact defense mechanisms against enteric infections, including the production of antimicrobial peptides. IL-22 binding protein (IL-22BP) is a soluble decoy encoded by the Il22ra2 gene that decreases IL-22 bioavailability, attenuating IL-22 signaling. The impact of IL-22BP on gut microbiota composition and functioning is poorly understood. We found that Il22ra2-/- mice are better protected against Clostridioides difficile and Citrobacter rodentium infections. This protection relied on IL-22-induced antimicrobial mechanisms before the infection occurred, rather than during the infection itself. Indeed, the gut microbiota of Il22ra2-/- mice mitigated infection of wild-type (WT) mice when transferred via cohousing or by cecal microbiota transplantation. Indicator species analysis of WT and Il22ra2-/- mice with and without cohousing disclosed that IL22BP deficiency yields a gut bacterial composition distinct from that of WT mice. Manipulation of dietary fiber content, measurements of intestinal short-chain fatty acids and oral treatment with acetate disclosed that resistance to C. difficile infection is related to increased production of acetate by Il22ra2-/--associated microbiota. Together, these findings suggest that IL-22BP represents a potential therapeutic target for those at risk for or with already manifest infection with this and perhaps other enteropathogens.

Animals↗

PubMed2004

Treponema pallidum fibronectin-binding proteins.

Putative adhesins were predicted by computer analysis of the Treponema pallidum genome. Two treponemal proteins, Tp0155 and Tp0483, demonstrated specific attachment to fibronectin, blocked bacterial adherence to fibronectin-coated slides, and supported attachment of fibronectin-producing mammalian cells. These results suggest Tp0155 and Tp0483 are fibronectin-binding proteins mediating T. pallidum-host interactions.

Adhesins, Bacterial↗

PubMed2026

Targeting the Fatty Acid Binding Protein 5-Specificity Protein 1 Axis Restores Enzalutamide Sensitivity by Suppressing Androgen Receptor/Androgen Receptor Splice Variant 7 Signaling: Implications for Prostate Cancer Therapy.

BACKGROUND: Castration-resistant prostate cancer (CRPC) remains a major clinical challenge driven by persistent androgen receptor (AR) signaling and constitutively active splice variants such as androgen receptor splice variant 7 (AR-V7), which confer resistance to therapies including enzalutamide. Although metabolic reprogramming contributes to disease progression, the integration of metabolic and transcriptional regulators sustaining therapeutic resistance remains incompletely understood. METHODS: We integrated clinical transcriptomic analysis of The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA-PRAD) cohort with mechanistic and functional validation in 22RV1 CRPC cells to investigate the role of the fatty acid binding protein 5-specificity protein 1 (FABP5-Sp1) regulatory axis. RESULTS: Transcriptomic analysis revealed that FABP5 is significantly upregulated in prostate tumors compared with normal tissue and increases with higher Gleason score. In contrast, AR and Sp1 exhibited heterogeneous expression patterns. Mechanistically, genetic ablation of FABP5 markedly reduced AR-V7 expression and restored sensitivity to enzalutamide, leading to suppression of AR signaling. Conversely, FABP5 overexpression increased Sp1 protein levels. Pharmacological inhibition of Sp1 using mithramycin A resulted in coordinated downregulation of FABP5, AR, and AR-V7, along with suppression of peroxisome proliferator-activated receptor gamma (PPARγ) signaling and downstream vascular endothelial growth factor A (VEGFA) expression. Functionally, Sp1 inhibition significantly reduced anchorage-independent growth and invasion. CONCLUSION: These findings define a FABP5-Sp1-AR/AR-V7 transcriptional-metabolic axis driving enzalutamide resistance in CRPC. Targeting FABP5 restores therapeutic sensitivity and represents a promising biomarker and therapeutic strategy in advanced prostate cancer.

AR-V7↗

PubMed2026

EWS-RNA Binding Protein 1: Structural Insights into Ewing Sarcoma by Conformational Dynamics Investigations.

BACKGROUND: Prior research has demonstrated that proteins play a significant role in the prognosis and treatments of various sarcomas, including Ewing sarcoma through the interplay of downstream signaling cascades. However, there is limited understanding about the strcucture conformation of EWSR1 and its structural implication in the prognosis of Ewsing Sarcoma by interaction with RNA molecules. AIMS: The primary goal of ongoing research is to determine how EWSR1 contributes to Ewing sarcoma. OBJECTIVE: The current study explores the complexity of EWSR1 structure and its conformational interactions with RNA in relation to Ewing sarcoma. METHODS: Here, we employed a comparative modeling approach to predict EWSR1 domains separately and assembled them into one structural unit using a DEMO server. Additionally, the RNA motifs interacting with EWSR1 were predicted, and the 3D model was built using RNAComposer. Protein-RNA docking and MD simulation studies were carried out to check the intermolecular interactions and stability behavior of docked EWSR1-RNA complexes. RESULTS: The overall results explore the structural insights into EWSR1 and their interactions with RNA, which may play a momentous role in co- and post-transcriptional regulation to control gene expression. CONCLUSION: Taken togather, our findings suggest that EWSR1 may be a useful therapeutic target for the diagnosis and management of Ewing sarcoma.

Sarcoma, Ewing↗

PubMed2026

Deciphering the Function and Structure of PA1216 as an S-Adenosyl-l-Methionine Binding Protein Using Differential Scanning Fluorimetry and Circular Dichroism.

Microbes produce bioactive secondary metabolites as toxins, pigments, or virulence factors. These specialized compounds are produced by nonribosomal peptide synthetases (NRPS), polyketide synthases (PKS), or hybrid NRPS/PKS pathways. The genes encoding NRPS and PKS reside in biosynthetic gene clusters (BGCs), some of which have no identified metabolite associated with them. Characterization of these orphan BGCs could provide insights into potential bioactive compounds that have yet to be discovered. Here, we characterize PA1216, a putative methyltransferase embedded within an NRPS BGC in Pseudomonas aeruginosa strain PAO1. We cloned, expressed, and purified PA1216, and developed an optimized differential scanning fluorimetry assay to measure its thermal stability, demonstrating concentration-dependent stabilization in the presence of established methyltransferase cofactors and inhibitors. We then adapted this assay for high-throughput screening of potential PA1216 substrates, identifying destabilizing compounds, including glycyl-glycine dipeptides, amino esters with aromatic or basic side chains, and N-Boc-protected amino acids. In contrast, sodium salts of organic acids stabilized PA1216. Lastly, we employed AlphaFold to construct a predictive model, revealing that PA1216 contains a Rossmann-like fold and a glycine-rich loop, typical of class I methyltransferases, and we corroborated these secondary structural elements using circular dichroism spectroscopy. Overall, these studies illuminate PA1216 function and establish a platform for characterizing cryptic gene clusters within secondary metabolic pathways.

Circular Dichroism↗

PubMed2024

The Lrs14 family of DNA-binding proteins as nucleoid-associated proteins in the Crenarchaeal order Sulfolobales.

Organization of archaeal chromatin combines bacterial, eukaryotic, and unique characteristics. Many archaeal lineages harbor a wide diversity of small and highly expressed nucleoid-associated proteins, which are involved in DNA structuring. In Sulfolobales, representing model organisms within the Crenarchaeota, Sul7d, Cren7, Sul10a, and Sul12a are well-characterized nucleoid-associated proteins. Here, we combine evidence that the Lrs14 family of DNA binders is part of the repertoire of nucleoid-associated proteins in Sulfolobales. Lrs14-encoding genes are widespread within genomes of different members of the Sulfolobales, typically encoded as four to nine homologs per genome. The Lrs14 proteins harbor a winged helix-turn-helix DNA-binding domain and are typified by a coiled-coil dimerization. They are characterized by distinct sequence- and structure-based features, including redox-sensitive motifs and residues targeted for posttranslational modification, allowing a further classification of the family into five conserved clusters. Lrs14-like proteins have unique DNA-organizing properties. By binding to the DNA nonsequence specifically and in a highly cooperative manner, with a slight preference for AT-rich promoter regions, they introduce DNA kinks and are able to affect transcription of adjacent transcription units either positively or negatively. Genes encoding Lrs14-type proteins display considerable differential expression themselves in response to various stress conditions, with certain homologs being specific to a particular stressor. Taken together, we postulate that members of the Lrs14 family can be considered nucleoid-associated proteins in Sulfolobales, combining a DNA-structuring role with a global gene expression role in response to stress conditions.

DNA-Binding Proteins↗

PubMed2003

Identification of a Treponema pallidum laminin-binding protein.

Host extracellular matrix (ECM) components represent ideal microbial adhesion targets that many pathogens use for colonization of tissues and initiation of infection. This study investigated the interaction of the spirochete Treponema pallidum with the ECM component laminin. To identify candidate laminin-binding adhesins, the T. pallidum genome was analyzed to predict open reading frames that encode putative outer membrane proteins, as these proteins interact directly with host ECM components. Subsequent recombinant expression of these proteins and analysis of their laminin-binding potential identified one protein, Tp0751, that demonstrated specific attachment to laminin. Tp0751 attached to laminin in a dose-dependent, saturable manner but did not attach to the ECM component collagen type I or IV or to the negative control proteins fetuin or bovine serum albumin. Sodium metaperiodate treatment of laminin reduced the Tp0751-laminin interaction in a concentration-dependent manner, suggesting that oligosaccharides play a role in this interaction. In addition, Tp0751-specific antibodies were detected in serum samples collected from both experimental and natural syphilis infections, indicating that Tp0751 is expressed in vivo during the course of infection. Collectively, these experiments identified Tp0751 as a laminin-binding protein that is expressed during infection and may be involved in attachment of T. pallidum to host tissues.

Adhesins, Bacterial↗

PubMed2003

Alternative interactions between the Tn7 transposase and the Tn7 target DNA binding protein regulate target immunity and transposition.

The Tn7 transposon avoids inserting into a target DNA that contains a pre-existing copy of Tn7. This phenomenon, known as 'target immunity', is established when TnsB, a Tn7 transposase subunit, binds to Tn7 sequences in the target DNA and mediates displacement of TnsC, a critical transposase activator, from the DNA. Paradoxically, TnsB-TnsC interactions are also required to promote transposon insertion. We have probed Tn7 target immunity by isolating TnsB mutants that mediate more frequent insertions into a potentially immune target DNA because they fail to provoke dissociation of TnsC from the DNA. We show that a single region of TnsB mediates the TnsB-TnsC interaction that underlies both target immunity and transposition, but that TnsA, the other transposase subunit, channels the TnsB-TnsC interaction toward transposition.

Amino Acid Sequence↗