@article{ReisSchwebsDietzetal.2018,
  author    = {Reis, Helena and Schwebs, Marie and Dietz, Sabrina and Janzen, Christian J. and Butter, Falk},
  title     = {TelAP1 links telomere complexes with developmental expression site silencing in African trypanosomes},
  series = {Nucleic Acids Research},
  volume    = {46},
  journal   = {Nucleic Acids Research},
  number    = {6},
  doi       = {10.1093/nar/gky028},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225180},
  pages     = {2820-2833},
  year      = {2018},
  abstract  = {During its life cycle, Trypanosoma brucei shuttles between a mammalian host and the tsetse fly vector. In the mammalian host, immune evasion of T. brucei bloodstream form (BSF) cells relies on antigenic variation, which includes monoallelic expression and periodic switching of variant surface glycoprotein (VSG) genes. The active VSG is transcribed from only 1 of the 15 subtelomeric expression sites (ESs). During differentiation from BSF to the insect-resident procyclic form (PCF), the active ES is transcriptionally silenced. We used mass spectrometry-based interactomics to determine the composition of telomere protein complexes in T. brucei BSF and PCF stages to learn more about the structure and functions of telomeres in trypanosomes. Our data suggest a different telomere complex composition in the two forms of the parasite. One of the novel telomere-associated proteins, TelAP1, forms a complex with telomeric proteins TbTRF, TbRAP1 and TbTIF2 and influences ES silencing kinetics during developmental differentiation.},
  language  = {en}
}
@article{MuellerCosentinoFoerstneretal.2018,
  author    = {M{\"u}ller, Laura S. M. and Cosentino, Ra{\´u}l O. and F{\"o}rstner, Konrad U. and Guizetti, Julien and Wedel, Carolin and Kaplan, Noam and Janzen, Christian J. and Arampatzi, Panagiota and Vogel, J{\"o}rg and Steinbiss, Sascha and Otto, Thomas D. and Saliba, Antoine-Emmanuel and Sebra, Robert P. and Siegel, T. Nicolai},
  title     = {Genome organization and DNA accessibility control antigenic variation in trypanosomes},
  series = {Nature},
  volume    = {563},
  journal   = {Nature},
  doi       = {10.1038/s41586-018-0619-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-224265},
  pages     = {121-125},
  year      = {2018},
  abstract  = {Many evolutionarily distant pathogenic organisms have evolved similar survival strategies to evade the immune responses of their hosts. These include antigenic variation, through which an infecting organism prevents clearance by periodically altering the identity of proteins that are visible to the immune system of the host1. Antigenic variation requires large reservoirs of immunologically diverse antigen genes, which are often generated through homologous recombination, as well as mechanisms to ensure the expression of one or very few antigens at any given time. Both homologous recombination and gene expression are affected by three-dimensional genome architecture and local DNA accessibility2,3. Factors that link three-dimensional genome architecture, local chromatin conformation and antigenic variation have, to our knowledge, not yet been identified in any organism. One of the major obstacles to studying the role of genome architecture in antigenic variation has been the highly repetitive nature and heterozygosity of antigen-gene arrays, which has precluded complete genome assembly in many pathogens. Here we report the de novo haplotype-specific assembly and scaffolding of the long antigen-gene arrays of the model protozoan parasite Trypanosoma brucei, using long-read sequencing technology and conserved features of chromosome folding4. Genome-wide chromosome conformation capture (Hi-C) reveals a distinct partitioning of the genome, with antigen-encoding subtelomeric regions that are folded into distinct, highly compact compartments. In addition, we performed a range of analyses—Hi-C, fluorescence in situ hybridization, assays for transposase-accessible chromatin using sequencing and single-cell RNA sequencing—that showed that deletion of the histone variants H3.V and H4.V increases antigen-gene clustering, DNA accessibility across sites of antigen expression and switching of the expressed antigen isoform, via homologous recombination. Our analyses identify histone variants as a molecular link between global genome architecture, local chromatin conformation and antigenic variation.},
  language  = {en}
}