MCB Seminar “Beyond Tethering Chromatin to the Nuclear Periphery: MSCellaneous Functions of the Nuclear Membrane Protein Lem2” By Sigurd Braun, Ph.D.
Eukaryotic genomes are partitioned into active and inactive domains, re-ferred to as euchromatin and heterochromatin. This topological and functional or-ganization is crucial for the differentiation into specialized cell types and plays an important role in cellular functions such as chromosome segregation, telomere maintenance, and genome stability.
A key type of transcriptionally silent chromatin conserved from fission yeast to humans is characterized by the covalent histone modification lysine 9 methyla-tion on H3 (H3K9me), which mediates the recruitment of members of the HP1 (heterochromatin protein) family. HP1 proteins are basic constituents of hetero-chromatin that appear to spread along DNA fiber, thereby creating a docking plat-form for various heterochromatic factors with individual functions. So far, we have only a poor understanding of how these different factors are specifically recruited and how these multiple interactions are coordinated on the heterochromatic HP1 platform.
Using a combination of genomics, functional genetics and proteomic ap-proaches in the powerful model organism fission yeast (Schizosaccharomyces pombe) that harbors the hallmarks of heterochromatin, research in the Braun lab seeks to dissect the regulatory networks that control the heterochromatic platform.