Regulation of DNA replication origins during normal development and tumorigenesis

The development of the human body starts from a single cell, fertilized egg, which divides about ten trillion times to form an adult human. During every cell division, the genome is duplicated with great accuracy by DNA replication and distributed with one copy to each of the two daughter cells. Understanding how the cell regulates DNA replication remains one of the most fundamental questions in biomedicine, because up to two-thirds of all cancers are caused by accumulation of errors during DNA replication. Pre-replicative complexes (pre-RCs) serve as essential precursors for DNA replication and their accurate levels are critical to alleviate genome instability associated with severe diseases, including cancer. Indeed, the overexpression of pre-RCs has been reported at early stages of variety of cancers making them an attractive target for cancer therapy. On the other hand, programmed genetic instability is part of the normal mammalian development, including heart cells. The aim of this project is to map differences in the mechanisms that regulate pathological and physiological genetic instability, an area that remains largely unexplored. We will identify signaling pathways responsible for optimal levels of pre-RCs and understand their contribution to genome instability during oncogene-induced tumorigenesis and programmed polyploidy during cardiomyocytes maturation in normal mammalian development. By combining physiologically relevant mammalian cellular models with state-of-the-art CRISPR-Cas9 genome editing, quantitative cell biology, genomics, and proteomics approaches we will address mechanism regulating accurate pre-RC formation and its role in physiological and oncogenic cellular transformation. Our findings will lay the foundations for the development of new anticancer drug targets and thereby expand therapeutic strategies for treatment of cancer associated with misregulated pre-RC levels and poor prognosis.