Heterochromatin-associated interactions of Drosophila HP1 with dADD1, HIPP1, and repetitive RNAs

We report chromatin-associated protein and RNA interactions of HP1a, indentified by BioTAP-XL mass spectrometry and sequencing. We identify an extensive list of both known and novel HP1a-interacting proteins from Drosophila S2 cells and from whole organisms across embryonic, larval and adult stages. BioTAP-XL protocol was used to identify HP1a interacting proteins through mass-spectrometry analysis. ChIP-seq-like pulldown/input samples were generated using BioTAP-XL to validate genomic distribution of the HP1a-BioTAP contructs, and the newly identified interacting proteins (CG8290 and CG3680); To examine the RNAs associated with the HP1a complexes, the RNA fraction of the BioTAP-XL pulldowns was analyzed using Illumina-based RNA-seq protocols, as well as Helicos direct RNA sequencing.