Publications by authors named "Sybille M Eibert"

3 Publications

  • Page 1 of 1

Cbf1p is required for chromatin remodeling at promoter-proximal CACGTG motifs in yeast.

J Biol Chem 2004 Jun 24;279(26):27116-23. Epub 2004 Apr 24.

Genetics Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.

Cbf1p is a basic-helix-loop-helix-zipper protein of Saccharomyces cerevisiae required for the function of centromeres and MET gene promoters, where it binds DNA via the consensus core motif CACRTG (R = A or G). At MET genes Cbf1p appears to function in both activator recruitment and chromatin-remodeling. Cbf1p has been implicated in the regulation of other genes, and CACRTG motifs are common in potential gene regulatory DNA. A recent genome-wide location analysis showed that the majority of intergenic CACGTG palindromes are bound by Cbf1p. Here we tested whether all potential Cbf1p binding motifs in the yeast genome are likely to be bound by Cbf1p using chromatin immunoprecipitation. We also tested which of the motifs are actually functional by assaying for Cbf1p-dependent chromatin remodeling. We show that Cbf1p binding and activity is restricted to palindromic CACGTG motifs in promoter-proximal regions. Cbf1p does not function through CACGTG motifs that occur in promoter-distal locations within coding regions nor where CACATG motifs occur alone except at centromeres. Cbf1p can be made to function at promoter-distal CACGTG motifs by overexpression, suggesting that the concentration of Cbf1p is normally limiting for binding and is biased to gene regulatory DNA by interactions with other factors. We conclude that Cbf1p is required for normal nucleosome positioning wherever the CACGTG motif occurs in gene regulatory DNA. Cbf1p has been shown to interact with the chromatin-remodeling ATPase Isw1p. Here we show that recruitment of Isw1p by Cbf1p is likely to be general but that Isw1p is only partially required for Cbf1p-dependent chromatin structures.
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http://dx.doi.org/10.1074/jbc.M403818200DOI Listing
June 2004

Cofilin peptide homologs interfere with immunological synapse formation and T cell activation.

Proc Natl Acad Sci U S A 2004 Feb 3;101(7):1957-62. Epub 2004 Feb 3.

Institute for Immunology, Ruprecht-Karls-University, D-69120 Heidelberg, Germany.

The formation of supramolecular activation clusters within the immunological synapse, crucial for sustained signaling and T lymphocyte activation, requires costimulation-dependent reorganization of the actin cytoskeleton. Here we have identified the actin-remodeling protein cofilin as a key player in this process. Cell-permeable peptides that block costimulation-induced cofilin/F-actin interactions in untransformed human T lymphocytes impair receptor capping and immunological synapse formation at the interface between T cells and antigen-presenting cells. As a consequence, T cell activation, as measured by cytokine production and proliferation, is inhibited.
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http://dx.doi.org/10.1073/pnas.0308282100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC357034PMC
February 2004

Actin cytoskeletal dynamics in T lymphocyte activation and migration.

J Leukoc Biol 2003 Jan;73(1):30-48

Institute for Immunology, Ruprecht-Karls-University, Im Neuenheimer Feld 305, D-69120 Heidelberg, Germany.

Dynamic rearrangements of the actin cytoskeleton are crucial for the function of numerous cellular elements including T lymphocytes. They are required for migration of T lymphocytes through the body to scan for the presence of antigens, as well as for the formation and stabilization of the immunological synapse at the interface between antigen-presenting cells and T lymphocytes. Supramolecular activation clusters within the immunological synapse play an important role for the initiation of T cell responses and for the execution of T cell effector functions. In addition to the T cell receptor/CD3 induced actin nucleation via Wasp/Arp2/3-activation, signals through accessory receptors of the T cell (i.e., costimulation) regulate actin cytoskeletal dynamics. In this regard, the actin-binding proteins cofilin and L-plastin represent prominent candidates linking accessory receptor stimulation to the rearrangement of the actin cytoskeleton. Cofilin enhances actin polymerization via its actin-severing activity, and as a long-lasting effect, cofilin generates novel actin monomers through F-actin depolymerization. L-plastin stabilizes actin filament structures by means of its actin-bundling activity.
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http://dx.doi.org/10.1189/jlb.0602272DOI Listing
January 2003