Function of CDYL in the regulation of chromatin structure

Within eukaryotic cells the environment for all genomic processes is chromatin. This structural highly dynamic polymeric molecule is composed of DNA and mainly histone proteins. Chromatin can be further divided into transcriptional active euchromatin or transcriptional inert heterochromatin. Post-translational modifications (PTM) of histones appear as key regulators of chromatin function thereby epitomizing the biochemical basis for epigenetic phenomena. One way how PTMs impact chromatin biology is via the recruitment of modification dependent "effector" proteins which further relay the modification to a particular biologic effect. Methylation of histone H3 at lysine 9 (H3K9) is considered one of the hallmarks of heterochromatin. One novel factor that was demonstrated recently to recognize this modification via a chromodomain is CDYL, indicating a possible function in organization of heterochromatin. This factor was shown to possess transcriptional repressor activity, probably via transient interaction with a repressor complex; however the function of CDYL in chromatin biology is not yet characterized. In this project I will analyze the role of CDYL in chromatin biology via biochemical, biophysical and cell biology approaches. To this end I will determine the subcellular localization of CDYL via fluorescence-microscopy and the chromatin related localization via genome wide mapping approaches. I will accurately analyze thermodynamic parameters of CDYL binding to chromatin and effects of this association on chromatin structure in vivo and in vitro. Further I will investigate consequences of CDYL binding on transcriptional regulation in vivo. To get a comprehensive understanding of CDYL direct and indirect functions in chromatin organization I will identify and characterize CDYL associated proteins as well as RNAs. The impact of these factors on CDYL chromatin- functions will be addressed via biochemical and biophysical methods. I expect the dataset generated from the suggested experiments to significantly expand our knowledge how CDYL may participate in heterochromatin formation.