Characterization of the role of the nuclear protein LmHus1 in DNA damage sensing and repair in the protozoan Leishmania

Abstract

LmHus1 is a protein expressed by the protozoan parasite Leishmania major, which mediates the resistance of these cells to genotoxic drugs. We have recently published an article in which we show that LmHus1 is a nuclear protein that, in response to hidroxyureia (HU) treatment, improves the parasite cell capability to cope with replicative stress. Eukaryotic cells have evolved checkpoint control systems that recognize altered DNA structures and halt cell cycle progression allowing DNA repair to take place. In these cells, the PCNA-related trimeric complex formed by the proteins Hus1, Rad9, and Rad1 is known to participate in the early steps of replicative stress sensing and signaling. In this proposal we aim the study of the molecular mechanisms in which LmHusl participates in Leishmania. We will investigate the possible partners of LmHus1, such as the product of the gene LmRad9/1, which may encode a bi-functional protein to replace Rad9 and Rad1 In the formation of the 9-1-1 complex in Leishmania. Based on preliminary results that suggested that not only LmHus1 but also LmRPA bind to the chromatin in response to HU treatment, we propose to investigate the dynamics of LmHus1 and LmRPA and their possible interaction in response to replicative stress. Another topic that we propose to investigate is the study of the participation of LmHus1 in the gene amplification phenomenon observed in these parasites. (AU)