The TAZ-CAMTA1 and YAP-TFE3 fusion proteins modulate the basal TAZ/YAP transcriptional program by recruiting the Ada2a-containing histone acetyltransferase complex [atacseq]

The WWTR1(TAZ)-CAMTA1 and YAP1-TFE3 gene fusions are disease defining gene alterations for epithelioid hemangioendothelioma, a vascular cancer. The resultant fusion proteins fuse the C terminus of CAMTA1 and TFE3 in frame to the N terminus of TAZ and YAP, respectively. An unbiased BioID-mass spectrometry/RNAi screen identified YEATS2 and ZZZ3 as components of the Ada2a-containing histone acetyltransferase complex and key interactors of both TAZ-CAMTA1 and YAP-TFE3. An integrative NGS approach including RNA-Seq, ChIP-Seq, and ATAC-Seq showed TAZ-CAMTA1 and YAP-TFE3 transcriptional programs overlap with TAZ and YAP but also drive expression of a novel transcriptome. The altered transcriptional program of the fusion proteins owing to altered DNA binding as well as shifts in the chromatin landscape. Transcriptionally accessible chromatin of SW872 liposarcoma cells transduced with fusion gene constructs generated by treatment with transposase and subsequent deep sequencing, in triplicate, using Illumina HiSeq4000.