Characterization of intra-S checkpoint in Trypanosoma cells

Abstract

Cell cycle is a high controlled process and ensures that each cell receives the same genetic material from the mother cell. Therefore, cell cycle perturbations can delay or arrest cell cycle progression. The biochemical pathway that triggers this delay/arrest is named checkpoint. In this sense, checkpoints can be defined as G1/S checkpoint, intra-S checkpoint and G2/M checkpoint. Here we intend to investigate the presence of intra-S checkpoint in Trypanosoma when double single stranded breaks occur. Moreover, we intend to evaluate if this checkpoint acts (i) blocking DNA replication fork elongation and / or (ii) blocking the firing of new replication origins. Once confirmed a response to block DNA replication in the presence of damaged DNA, we intend to evaluate the role of ATM and ATR in this process. T. cruzi and T. brucei cells will be analyzed. Since these cells are early divergent eukaryotes this project aims to characterize intra-S checkpoint in these parasites and eventually describe new strategies to deal with damaged DNA. Moreover, T. brucei, but not T. cruzi, uses a double stranded break, generated during DNA replication, to induce the recombination process essential for antigenic variation and consequently for the success of infection. Therefore, understand how T. brucei deals with DNA damage may contribute to our knowledge concerning the process of T. brucei infection. It is important to say that if we observe lacking of intra-S checkpoint (which would be a very interesting data) we intend to verify the role of ATM and ATR in the G1/S or G2/M checkpoint in the presence of damaged DNA. (AU)