Sebastian Darr

Publications

• Tripeptidyl Peptidase II Is Required for c-MYC-Induced Centriole Overduplication and a Novel Therapeutic Target in c-MYC-Associated Neoplasms.

  Stefan Duensing, Sebastian Darr, Rolando Cuevas, Nadja Melquiot, Anthony G Brickner, Anette Duensing, Karl Münger

  Genes & cancer. 09/2010; 1(9):883-92.

  Centrosome aberrations are frequently detected in c-MYC-associated human malignancies. Here, we show that c-MYC-induced centrosome and centriole overduplication critically depend on the protease tripeptidyl peptidase II (TPPII). We found that TPPII localizes to centrosomes and that overexpression of... [more] Centrosome aberrations are frequently detected in c-MYC-associated human malignancies. Here, we show that c-MYC-induced centrosome and centriole overduplication critically depend on the protease tripeptidyl peptidase II (TPPII). We found that TPPII localizes to centrosomes and that overexpression of TPPII, similar to c-MYC, can disrupt centriole duplication control and cause centriole multiplication, a process during which maternal centrioles nucleate the formation of more than a single daughter centriole. We report that inactivation of TPPII using chemical inhibitors or siRNA-mediated protein knockdown effectively reduced c-MYC-induced centriole overduplication. Remarkably, the potent and selective TPPII inhibitor butabindide not only potently suppressed centriole aberrations but also caused significant cell death and growth suppression in aggressive human Burkitt lymphoma cells with c-MYC overexpression. Taken together, these results highlight the role of TPPII in c-MYC-induced centriole overduplication and encourage further studies to explore TPPII as a novel antineoplastic drug target.

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• 3.26

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  Phylogeny and primary structure analysis of fiber shafts of all human adenovirus types for rational design of adenoviral gene therapy vectors.

  Sebastian Darr, Ijad Madisch, Sören Hofmayer, Fabienne Rehren, Albert Heim

  The Journal of general virology. 09/2009;

  The fiber shaft of human adenoviruses (HAdV) is essential for bringing the penton base in proximity to the secondary cellular receptor. Fiber shaft sequences of all 53 HAdV types were studied. Phylogeny of the fiber shaft revealed clustering corresponding to the HAdV species concept. An intraspecies... [more] The fiber shaft of human adenoviruses (HAdV) is essential for bringing the penton base in proximity to the secondary cellular receptor. Fiber shaft sequences of all 53 HAdV types were studied. Phylogeny of the fiber shaft revealed clustering corresponding to the HAdV species concept. An intraspecies recombination hot spot was found at the shaft/knob boundary, a highly conserved sequence stretch. For example, HAdV-D20 clustered with -D23 in the fiber shaft but with HAdV-D47 in the fiber knob. Although all shafts exhibited the typical pseudorepeats, sequence divergence was found to be as high as 92% interspecies and 54% intraspecies. In contrast to a previous study, a flexibility motif (KXGGLXFD/N) was found in eight HAdV-D types whereas the putative heparan sulfate binding site (KKTK) was only found in species HAdV-C. Our results suggest that pseudotyping of gene therapy vectors at the shaft/knob-boundary is feasible but flexibility data of shafts should be considered.

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• 8.20

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  Antiviral activity of cidofovir and ribavirin against the new human adenovirus subtype 14a that is associated with severe pneumonia.

  Sebastian Darr, Ijad Madisch, Albert Heim

  Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 10/2008; 47(5):731-2.

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• Unique Sequence Features of the Human Adenovirus 31 Complete Genomic Sequence are Conserved in Clinical Isolates

  Soeren Hofmayer, Sebastian Darr, Fabienne Rehren, Albert Heim, Ijad Madisch

  Background: Human adenoviruses (HAdV) are causing a broad spectrum of diseases. One of the most severe forms of adenovirus infection is a disseminated disease resulting in significant morbidity and mortality. Several reports in recent years have identified HAdV-31 from species A (HAdV-A31) as a caus... [more] Background: Human adenoviruses (HAdV) are causing a broad spectrum of diseases. One of the most severe forms of adenovirus infection is a disseminated disease resulting in significant morbidity and mortality. Several reports in recent years have identified HAdV-31 from species A (HAdV-A31) as a cause of disseminated disease in children following haematopoetic stem cell transplantation (hSCT) and liver transplantation. We sequenced and analyzed the complete genome of the HAdV-A31 prototype strain to uncover unique sequence motifs associated with its high virulence. Moreover, we sequenced coding regions known to be essential for tropism and virulence (early transcription units E1A, E3, E4, the fiber knob and the penton base) of HAdV-A31 clinical isolates from patients with disseminated disease. Results: The genome size of HAdV-A31 is 33763 base pairs (bp) in length with a GC content of 46.36%. Nucleotide alignment to the closely related HAdV-A12 revealed an overall homology of 84.2%. The genome organization into early, intermediate and late regions is similar to HAdV-A12. Sequence analysis of the prototype strain showed unique sequence features such as an immunoglobulin-like domain in the species A specific gene product E3 CR1 beta and a potentially integrin binding RGD motif in the C-terminal region of the protein IX. These features were conserved in all analyzed clinical isolates. Overall, amino acid sequences of clinical isolates were highly conserved compared to the prototype (99.2 to 100%), but a synonymous/non synonymous ratio (S/N) of 2.36 in E3 CR1 beta suggested positive selection. Conclusion: Unique sequence features of HAdV-A31 may enhance its ability to escape the host's immune surveillance and may facilitate a promiscuous tropism for various tissues. Moderate evolution of clinical isolates did not indicate the emergence of new HAdV-A31 subtypes in the recent years.