@article{RaketteDonatOhlsenetal.2012, author = {Rakette, Sonja and Donat, Stefanie and Ohlsen, Knut and Stehle, Thilo}, title = {Structural Analysis of Staphylococcus aureus Serine/Threonine Kinase PknB}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {6}, doi = {10.1371/journal.pone.0039136}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135369}, pages = {e39136}, year = {2012}, abstract = {Effective treatment of infections caused by the bacterium Staphylococcus aureus remains a worldwide challenge, in part due to the constant emergence of new strains that are resistant to antibiotics. The serine/threonine kinase PknB is of particular relevance to the life cycle of S. aureus as it is involved in the regulation of purine biosynthesis, autolysis, and other central metabolic processes of the bacterium. We have determined the crystal structure of the kinase domain of PknB in complex with a non-hydrolyzable analog of the substrate ATP at 3.0 angstrom resolution. Although the purified PknB kinase is active in solution, it crystallized in an inactive, autoinhibited state. Comparison with other bacterial kinases provides insights into the determinants of catalysis, interactions of PknB with ligands, and the pathway of activation.}, language = {en} } @article{JaegerPernitzschRichteretal.2012, author = {J{\"a}ger, Dominik and Pernitzsch, Sandy R. and Richter, Andreas S. and Backofen, Rolf and Sharma, Cynthia M. and Schmitz, Ruth A.}, title = {An archaeal sRNA targeting cis- and trans-encoded mRNAs via two distinct domains}, series = {Nucleic Acids Research}, volume = {40}, journal = {Nucleic Acids Research}, number = {21}, doi = {10.1093/nar/gks847}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134972}, pages = {10964-10979}, year = {2012}, abstract = {We report on the characterization and target analysis of the small (s) RNA\(_{162}\) in the methanoarchaeon Methanosarcina mazei. Using a combination of genetic approaches, transcriptome analysis and computational predictions, the bicistronic MM2441-MM2440 mRNA encoding the transcription factor MM2441 and a protein of unknown function was identified as a potential target of this sRNA, which due to processing accumulates as three stabile 5' fragments in late exponential growth. Mobility shift assays using various mutants verified that the non-structured single-stranded linker region of sRNA\(_{162}\) (SLR) base-pairs with the MM2440-MM2441 mRNA internally, thereby masking the predicted ribosome binding site of MM2441. This most likely leads to translational repression of the second cistron resulting in dis-coordinated operon expression. Analysis of mutant RNAs in vivo confirmed that the SLR of sRNA\(_{162}\) is crucial for target interactions. Furthermore, our results indicate that sRNA\(_{162}\)-controlled MM2441 is involved in regulating the metabolic switch between the carbon sources methanol and methylamine. Moreover, biochemical studies demonstrated that the 50 end of sRNA\(_{162}\) targets the 5'-untranslated region of the cis-encoded MM2442 mRNA. Overall, this first study of archaeal sRNA/mRNA-target interactions unraveled that sRNA\(_{162}\) acts as an antisense (as) RNA on cis- and trans-encoded mRNAs via two distinct domains, indicating that cis-encoded asRNAs can have larger target regulons than previously anticipated.}, language = {en} } @article{HickeySridharWestermannetal.2012, author = {Hickey, Scott F. and Sridhar, Malathy and Westermann, Alexander J. and Qin, Qian and Vijayendra, Pooja and Liou, Geoffrey and Hammond, Ming C.}, title = {Transgene regulation in plants by alternative splicing of a suicide exon}, series = {Nucleic Acids Research}, volume = {40}, journal = {Nucleic Acids Research}, number = {10}, doi = {10.1093/nar/gks032}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134724}, pages = {4701-4710}, year = {2012}, abstract = {Compared to transcriptional activation, other mechanisms of gene regulation have not been widely exploited for the control of transgenes. One barrier to the general use and application of alternative splicing is that splicing-regulated transgenes have not been shown to be reliably and simply designed. Here, we demonstrate that a cassette bearing a suicide exon can be inserted into a variety of open reading frames (ORFs), generating transgenes whose expression is activated by exon skipping in response to a specific protein inducer. The surprisingly minimal sequence requirements for the maintenance of splicing fidelity and regulation indicate that this splicing cassette can be used to regulate any ORF containing one of the amino acids Glu, Gln or Lys. Furthermore, a single copy of the splicing cassette was optimized by rational design to confer robust gene activation with no background expression in plants. Thus, conditional splicing has the potential to be generally useful for transgene regulation.}, language = {en} } @article{MasicHurdayalNieuwenhuizenetal.2012, author = {Masic, Anita and Hurdayal, Ramona and Nieuwenhuizen, Natalie E. and Brombacher, Frank and Moll, Heidrun}, title = {Dendritic Cell-Mediated Vaccination Relies on Interleukin-4 Receptor Signaling to Avoid Tissue Damage after Leishmania major Infection of BALB/c Mice}, series = {PLoS Neglected Tropical Diseases}, volume = {6}, journal = {PLoS Neglected Tropical Diseases}, number = {7}, doi = {10.1371/journal.pntd.0001721}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133869}, year = {2012}, abstract = {Prevention of tissue damages at the site of Leishmania major inoculation can be achieved if the BALB/c mice are systemically given L. major antigen (LmAg)-loaded bone marrow-derived dendritic cells (DC) that had been exposed to CpG-containing oligodeoxynucleotides (CpG ODN). As previous studies allowed establishing that interleukin-4 (IL-4) is involved in the redirection of the immune response towards a type 1 profile, we were interested in further exploring the role of IL-4. Thus, wild-type (wt) BALB/c mice or DC-specific IL-4 receptor \(\alpha\) (IL-4R \(\alpha\))-deficient (CD11c\(^{cre}\)IL-4R \(\alpha^{-/lox}\) BALB/c mice were given either wt or IL-4R \(\alpha\)-deficient LmAg-loaded bone marrow-derived DC exposed or not to CpG ODN prior to inoculation of 2x10\(^5\) stationary-phase L. major promastigotes into the BALB/c footpad. The results provide evidence that IL4/IL-4R alpha-mediated signaling in the vaccinating DC is required to prevent tissue damage at the site of L. major inoculation, as properly conditioned wt DC but not IL-4R alpha-deficient DC were able to confer resistance. Furthermore, uncontrolled L. major population size expansion was observed in the footpad and the footpad draining lymph nodes of CD11c\(^{cre}\)IL-4R \(\alpha^{-/lox}\) mice immunized with CpG ODN-exposed LmAg-loaded IL-4R \(\alpha\)-deficient DC, indicating the influence of IL-4R \(\alpha\)-mediated signaling in host DC to control parasite replication. In addition, no footpad damage occurred in BALB/c mice that were systemically immunized with LmAg-loaded wt DC doubly exposed to CpG ODN and recombinant IL-4. We discuss these findings and suggest that the IL4/IL4R \(\alpha\) signaling pathway could be a key pathway to trigger when designing vaccines aimed to prevent damaging processes in tissues hosting intracellular microorganisms.}, language = {en} } @article{PilsKoppPetersonetal.2012, author = {Pils, Stefan and Kopp, Kathrin and Peterson, Lisa and Tascon, Julia Delgado and Nyffenegger-Jann, Naja J. and Hauck, Christof R.}, title = {The Adaptor Molecule Nck Localizes the WAVE Complex to Promote Actin Polymerization during CEACAM3-Mediated Phagocytosis of Bacteria}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {3}, doi = {10.1371/journal.pone.0032808}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131747}, pages = {e32808}, year = {2012}, abstract = {Background: CEACAM3 is a granulocyte receptor mediating the opsonin-independent recognition and phagocytosis of human-restricted CEACAM-binding bacteria. CEACAM3 function depends on an intracellular immunoreceptor tyrosine-based activation motif (ITAM)-like sequence that is tyrosine phosphorylated by Src family kinases upon receptor engagement. The phosphorylated ITAM-like sequence triggers GTP-loading of Rac by directly associating with the guanine nucleotide exchange factor (GEF) Vav. Rac stimulation in turn is critical for actin cytoskeleton rearrangements that generate lamellipodial protrusions and lead to bacterial uptake. Principal Findings: In our present study we provide biochemical and microscopic evidence that the adaptor proteins Nck1 and Nck2, but not CrkL, Grb2 or SLP-76, bind to tyrosine phosphorylated CEACAM3. The association is phosphorylation-dependent and requires the Nck SH2 domain. Overexpression of the isolated Nck1 SH2 domain, RNAi-mediated knock-down of Nck1, or genetic deletion of Nck1 and Nck2 interfere with CEACAM3-mediated bacterial internalization and with the formation of lamellipodial protrusions. Nck is constitutively associated with WAVE2 and directs the actin nucleation promoting WAVE complex to tyrosine phosphorylated CEACAM3. In turn, dominant-negative WAVE2 as well as shRNA-mediated knock-down of WAVE2 or the WAVE-complex component Nap1 reduce internalization of bacteria. Conclusions: Our results provide novel mechanistic insight into CEACAM3-initiated phagocytosis. We suggest that the CEACAM3 ITAM-like sequence is optimized to co-ordinate a minimal set of cellular factors needed to efficiently trigger actin-based lamellipodial protrusions and rapid pathogen engulfment.}, language = {en} } @article{RamachandranShearerJacobetal.2012, author = {Ramachandran, Vinoy K. and Shearer, Neil and Jacob, Jobin J. and Sharma, Cynthia M. and Thompson, Arthur}, title = {The architecture and ppGpp-dependent expression of the primary transcriptome of Salmonella Typhimurium during invasion gene expression}, series = {BMC Genomics}, volume = {13}, journal = {BMC Genomics}, number = {25}, doi = {10.1186/1471-2164-13-25}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130625}, year = {2012}, abstract = {Background: Invasion of intestinal epithelial cells by Salmonella enterica serovar Typhimurium (S. Typhimurium) requires expression of the extracellular virulence gene expression programme (STEX), activation of which is dependent on the signalling molecule guanosine tetraphosphate (ppGpp). Recently, next-generation transcriptomics (RNA-seq) has revealed the unexpected complexity of bacterial transcriptomes and in this report we use differential RNA sequencing (dRNA-seq) to define the high-resolution transcriptomic architecture of wildtype S. Typhimurium and a ppGpp null strain under growth conditions which model STEX. In doing so we show that ppGpp plays a much wider role in regulating the S. Typhimurium STEX primary transcriptome than previously recognised. Results: Here we report the precise mapping of transcriptional start sites (TSSs) for 78\% of the S. Typhimurium open reading frames (ORFs). The TSS mapping enabled a genome-wide promoter analysis resulting in the prediction of 169 alternative sigma factor binding sites, and the prediction of the structure of 625 operons. We also report the discovery of 55 new candidate small RNAs (sRNAs) and 302 candidate antisense RNAs (asRNAs). We discovered 32 ppGpp-dependent alternative TSSs and determined the extent and level of ppGpp-dependent coding and non-coding transcription. We found that 34\% and 20\% of coding and non-coding RNA transcription respectively was ppGpp-dependent under these growth conditions, adding a further dimension to the role of this remarkable small regulatory molecule in enabling rapid adaptation to the infective environment. Conclusions: The transcriptional architecture of S. Typhimurium and finer definition of the key role ppGpp plays in regulating Salmonella coding and non-coding transcription should promote the understanding of gene regulation in this important food borne pathogen and act as a resource for future research.}, language = {en} } @article{WangChenMinevetal.2012, author = {Wang, Huiqiang and Chen, Nanhai G. and Minev, Boris R. and Szalay, Aladar A.}, title = {Oncolytic vaccinia virus GLV-1h68 strain shows enhanced replication in human breast cancer stem-like cells in comparison to breast cancer cells}, series = {Journal of Translational Medicine}, volume = {10}, journal = {Journal of Translational Medicine}, number = {167}, doi = {10.1186/1479-5876-10-167}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130019}, year = {2012}, abstract = {Background: Recent data suggest that cancer stem cells (CSCs) play an important role in cancer, as these cells possess enhanced tumor-forming capabilities and are responsible for relapses after apparently curative therapies have been undertaken. Hence, novel cancer therapies will be needed to test for both tumor regression and CSC targeting. The use of oncolytic vaccinia virus (VACV) represents an attractive anti-tumor approach and is currently under evaluation in clinical trials. The purpose of this study was to demonstrate whether VACV does kill CSCs that are resistant to irradiation and chemotherapy. Methods: Cancer stem-like cells were identified and separated from the human breast cancer cell line GI-101A by virtue of increased aldehyde dehydrogenase 1 (ALDH1) activity as assessed by the ALDEFLUOR assay and cancer stem cell-like features such as chemo-resistance, irradiation-resistance and tumor-initiating were confirmed in cell culture and in animal models. VACV treatments were applied to both ALDEFLUOR-positive cells in cell culture and in xenograft tumors derived from these cells. Moreover, we identified and isolated CD44\(^+\)CD24\(^+\)ESA\(^+\) cells from GI-101A upon an epithelial-mesenchymal transition (EMT). These cells were similarly characterized both in cell culture and in animal models. Results: We demonstrated for the first time that the oncolytic VACV GLV-1h68 strain replicated more efficiently in cells with higher ALDH1 activity that possessed stem cell-like features than in cells with lower ALDH1 activity. GLV-1h68 selectively colonized and eventually eradicated xenograft tumors originating from cells with higher ALDH1 activity. Furthermore, GLV-1h68 also showed preferential replication in CD44\(^+\)CD24\(^+\)ESA\(^+\) cells derived from GI-101A upon an EMT induction as well as in xenograft tumors originating from these cells that were more tumorigenic than CD44\(^+\)CD24\(^-\)ESA\(^+\) cells. Conclusions: Taken together, our findings indicate that GLV-1h68 efficiently replicates and kills cancer stem-like cells. Thus, GLV-1h68 may become a promising agent for eradicating both primary and metastatic tumors, especially tumors harboring cancer stem-like cells that are resistant to chemo and/or radiotherapy and may be responsible for recurrence of tumors.}, language = {en} } @article{GentschevAdelfingerJosupeitetal.2012, author = {Gentschev, Ivaylo and Adelfinger, Marion and Josupeit, Rafael and Rudolph, Stephan and Ehrig, Klaas and Donat, Ulrike and Weibel, Stephanie and Chen, Nanhai G. and Yu, Yong A. and Zhang, Qian and Heisig, Martin and Thamm, Douglas and Stritzker, Jochen and MacNeill, Amy and Szalay, Aladar A.}, title = {Preclinical Evaluation of Oncolytic Vaccinia Virus for Therapy of Canine Soft Tissue Sarcoma}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {5}, doi = {10.1371/journal.pone.0037239}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129998}, year = {2012}, abstract = {Virotherapy using oncolytic vaccinia virus (VACV) strains is one promising new strategy for canine cancer therapy. In this study we describe the establishment of an in vivo model of canine soft tissue sarcoma (CSTS) using the new isolated cell line STSA-1 and the analysis of the virus-mediated oncolytic and immunological effects of two different Lister VACV LIVP1.1.1 and GLV-1h68 strains against CSTS. Cell culture data demonstrated that both tested VACV strains efficiently infected and destroyed cells of the canine soft tissue sarcoma line STSA-1. In addition, in our new canine sarcoma tumor xenograft mouse model, systemic administration of LIVP1.1.1 or GLV-1h68 viruses led to significant inhibition of tumor growth compared to control mice. Furthermore, LIVP1.1.1 mediated therapy resulted in almost complete tumor regression and resulted in long-term survival of sarcoma-bearing mice. The replication of the tested VACV strains in tumor tissues led to strong oncolytic effects accompanied by an intense intratumoral infiltration of host immune cells, mainly neutrophils. These findings suggest that the direct viral oncolysis of tumor cells and the virus-dependent activation of tumor-associated host immune cells could be crucial parts of anti-tumor mechanism in STSA-1 xenografts. In summary, the data showed that both tested vaccinia virus strains and especially LIVP1.1.1 have great potential for effective treatment of CSTS.}, language = {en} } @article{FroehlichPapenfortBergeretal.2012, author = {Fr{\"o}hlich, Kathrin S. and Papenfort, Kai and Berger, Allison A. and Vogel, J{\"o}rg}, title = {A conserved RpoS-dependent small RNA controls the synthesis of major porin OmpD}, series = {Nucleic Acids Research}, volume = {40}, journal = {Nucleic Acids Research}, number = {8}, doi = {10.1093/nar/gkr1156}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134230}, pages = {3623-3640}, year = {2012}, abstract = {A remarkable feature of many small non-coding RNAs (sRNAs) of Escherichia coli and Salmonella is their accumulation in the stationary phase of bacterial growth. Several stress response regulators and sigma factors have been reported to direct the transcription of stationary phase-specific sRNAs, but a widely conserved sRNA gene that is controlled by the major stationary phase and stress sigma factor, Sigma(S) (RpoS), has remained elusive. We have studied in Salmonella the conserved SdsR sRNA, previously known as RyeB, one of the most abundant stationary phase-specific sRNAs in E. coli. Alignments of the sdsR promoter region and genetic analysis strongly suggest that this sRNA gene is selectively transcribed by Sigma(S). We show that SdsR down-regulates the synthesis of the major Salmonella porin OmpD by Hfq-dependent base pairing; SdsR thus represents the fourth sRNA to regulate this major outer membrane porin. Similar to the InvR, MicC and RybB sRNAs, SdsR recognizes the ompD mRNA in the coding sequence, suggesting that this mRNA may be primarily targeted downstream of the start codon. The SdsR-binding site in ompD was localized by 3'-RACE, an experimental approach that promises to be of use in predicting other sRNA-target interactions in bacteria.}, language = {en} } @article{MakoahNigelArndtPradel2012, author = {Makoah Nigel, Animake and Arndt, Hans-Dieter and Pradel, Gabriele}, title = {The proteasome of malaria parasites: A multi-stage drug target for chemotherapeutic intervention?}, series = {International Journal for Parasitology: Drugs and Drug Resistance}, volume = {2}, journal = {International Journal for Parasitology: Drugs and Drug Resistance}, doi = {10.1016/j.ijpddr.2011.12.001}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137777}, pages = {1-10}, year = {2012}, abstract = {The ubiquitin/proteasome system serves as a regulated protein degradation pathway in eukaryotes, and is involved in many cellular processes featuring high protein turnover rates, such as cell cycle control, stress response and signal transduction. In malaria parasites, protein quality control is potentially important because of the high replication rate and the rapid transformations of the parasite during life cycle progression. The proteasome is the core of the degradation pathway, and is a major proteolytic complex responsible for the degradation and recycling of non-functional ubiquitinated proteins. Annotation of the genome for Plasmodium falciparum, the causative agent of malaria tropica, revealed proteins with similarity to human 26S proteasome subunits. In addition, a bacterial ClpQ/hslV threonine peptidase-like protein was identified. In recent years several independent studies indicated an essential function of the parasite proteasome for the liver, blood and transmission stages. In this review, we compile evidence for protein recycling in Plasmodium parasites and discuss the role of the 26S proteasome as a prospective multi-stage target for antimalarial drug discovery programs.}, language = {en} }