TY  - JOUR
A1  - Gross, Henrik
A1  - Hennard, Christine
A1  - Masouris, Ilias
A1  - Cassel, Christian
A1  - Barth, Stephanie
A1  - Stober-Grässer, Ute
A1  - Mamiani, Alfredo
A1  - Moritz, Bodo
A1  - Ostareck, Dirk
A1  - Ostareck-Lederer, Antje
A1  - Neuenkirchen, Nils
A1  - Fischer, Utz
A1  - Deng, Wen
A1  - Leonhardt, Heinrich
A1  - Noessner, Elfriede
A1  - Kremmer, Elisabeth
A1  - Grässer, Friedrich A.
T1  - Binding of the Heterogeneous Ribonucleoprotein K (hnRNP K) to the Epstein-Barr Virus Nuclear Antigen 2 (EBNA2) Enhances Viral LMP2A Expression
JF  - PLoS One
N2  - The Epstein-Barr Virus (EBV) -encoded EBNA2 protein, which is essential for the in vitro transformation of B-lymphocytes, interferes with cellular processes by binding to proteins via conserved sequence motifs. Its Arginine-Glycine (RG) repeat element contains either symmetrically or asymmetrically di-methylated arginine residues (SDMA and ADMA, respectively). EBNA2 binds via its SDMA-modified RG-repeat to the survival motor neurons protein (SMN) and via the ADMA-RG-repeat to the NP9 protein of the human endogenous retrovirus K (HERV-K (HML-2) Type 1). The hypothesis of this work was that the methylated RG-repeat mimics an epitope shared with cellular proteins that is used for interaction with target structures. With monoclonal antibodies against the modified RG-repeat, we indeed identified cellular homologues that apparently have the same surface structure as methylated EBNA2. With the SDMA-specific antibodies, we precipitated the Sm protein D3 (SmD3) which, like EBNA2, binds via its SDMA-modified RG-repeat to SMN. With the ADMA-specific antibodies, we precipitated the heterogeneous ribonucleoprotein K (hnRNP K). Specific binding of the ADMA-antibody to hnRNP K was demonstrated using E. coli expressed/ADMA-methylated hnRNP K. In addition, we show that EBNA2 and hnRNP K form a complex in EBV-infected B-cells. Finally, hnRNP K, when co-expressed with EBNA2, strongly enhances viral latent membrane protein 2A (LMP2A) expression by an unknown mechanism as we did not detect a direct association of hnRNP K with DNA-bound EBNA2 in gel shift experiments. Our data support the notion that the methylated surface of EBNA2 mimics the surface structure of cellular proteins to interfere with or co-opt their functional properties.
KW  - SM proteins
KW  - protein argentine methyltranserase
KW  - motor-neuron protein
KW  - RNA-polymerase-II
KW  - messenger RNA
KW  - C-MYC
KW  - gene expression
KW  - splicing factor
KW  - down regulation
KW  - living cells
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133707
VL  - 7
IS  - 8
ER  - 
TY  - JOUR
A1  - Fröhlich, Kathrin S.
A1  - Papenfort, Kai
A1  - Berger, Allison A.
A1  - Vogel, Jörg
T1  - A conserved RpoS-dependent small RNA controls the synthesis of major porin OmpD
JF  - Nucleic Acids Research
N2  - 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.
KW  - shock sigma factor
KW  - general stress response
KW  - down regulation
KW  - stationary phase
KW  - salmonella enterica
KW  - messenger RNA
KW  - escherichia coli
KW  - enterica serovar typhimurium
KW  - outer-membrane proteins
KW  - small noncoding RNAs
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134230
VL  - 40
IS  - 8
ER  -