ATAC and Mediator coactivators form a stable complex and regulates a set of non-coding RNA genes. Mus musculus

The ATAC histone acetyl-transferase (HAT) and the Mediator coactivator complexes regulate independent and distinct steps during transcription initiation and elongation. Here we report the identification of a new stable molecular assembly formed between the ATAC and the Mediator complex in mouse embryonic stem cells. Moreover, we identify LUZP1 as a subunit of this meta coactivator complex (MECO). Finally, we demonstrate that MECO regulates a subset of RNA polymerase II transcribed non-coding RNA genes. Our findings establish that transcription coactivator complexes can form stable sub-complexes in order to facilitate their combined actions on specific target genes. Overall design: For ChIP-seq analysis, 300µg of chromatin (DNA) was incubated with GST (mock), LUZP1 and GCN5 antibodies. Retrieved purified DNA was sequenced using Illumina Genome Analyzer II following manufacturer recommendations. Illumina raw files were aligned against reference (mouse mm9) genome using the eland program allowing one mismatch. Enrichment clusters were detected using MACS (Zhang et al., 2008). The retrieved peaks were filtered (max size 1000bp, min size 100bp) and repeat masked, to establish the final binding sites lists. Peaks were annotated using the GPAT web server (Krebs et al., 2008) using ENSEMBL gene 57 database.