Investigation of Oncogene-Induced Alterations in Chromatin Organization In Vitro by Structured Illumination Microscopy

Oncogenes activation may lead to alterations in chromatin organization at the nanoscale by interfering with fundamental processes such as DNA transcription, DNA replication, and DNA Damage Response [1]. The in vitro observation of these molecular processes is crucial to understand how oncogenes can alter chromatin organization leading to tumor formation. Among all the available techniques to address this issue, optical super-resolution microscopy stands out for its potential in revealing the distribution of molecules within intact cell nuclei. Here we apply structured illumination microscopy (SIM)[2] to investigate a model of oncogene activation in an engineered cell line, U937-PR9, derived from Acute Promyelocytic Leukemia (APL) patients. In APL, 70% of the patients present a mutation that causes the formation of a fusion protein PML-RARalpha. This model allows us to selectively activate the PML-RAR …