Dissecting the role of MYTHO in the DNA damage response

One of the main causes of cellular senescence and of the onset of age-related pathologies, such as cancer and neurodegenerative diseases, is genomic instability. The exposure to harmful substances, both endogenous and exogenous agents, may lead to DNA damage. Even though, under physiological conditions the cell is provided with mechanisms that allow to sense and repair the lesions, there are cases in which the DNA damage response (DDR) is activated. DDR is composed by a set of sensors, mediators and transducers that induce the cell cycle to stop in order to avoid the replication of the error. Some recent studies have identified and characterized a new Forkhead Box O (Fox-O) dependent gene, named Mytho (Macroautophagy and YouTH Optimizer), which could be involved in the maintenance of genomic stability. With the aim of deepening understanding about the effects of the absence of MYTHO in the DNA damage response (DDR), murine myoblasts (C2C12) wild-type and MYTHO knock-out were treated with etoposide, an antineoplastic agent which causes double-strand break. In order to investigate the molecular effects of the silencing of MYTHO, the expression and the phosphorylation levels of the proteins involved in the DDR pathways, such as H2AX and p53, were analyzed through Western Blot assays. Since MYTHO could also be indirectly involved in the DNA repair process by interacting with the enzymes responsible for the dNTPs synthesis, a cloning experiment was set up to clarify its role in the maintenance of genomic integrity.