Dynamics of DNA Replication during Male Gametogenesis in the Malaria Parasite Plasmodium Falciparum

Malaria parasites undergo a single phase of sexual reproduction in their complex lifecycle. It involves specialised, sexually committed cells called gametocytes, which develop rapidly into mature gametes and mate upon entering the mosquito midgut. Gamete development is unique, involving unprecedentedly fast replication to produce male gametes. Within similar to 15 minutes a male gametocyte replicates its similar to 23 Mb genome three times to produce 8 genomes, segregates these into newly-assembled flagellated gametes and releases them to seek female gametes. Here, for the first time, we use fluorescent labelling of de novo DNA synthesis to follow this process at the whole-cell and single-molecule levels. We make several novel observations, including characterising the origin recognition complex protein Orc1 for the first time in gametocytes, finding that cytokinesis is uncoupled from DNA replication (implying a lack of cell cycle checkpoints), and that the single-molecule dynamics of DNA replication are entirely different from the dynamics in asexual schizogony.

Automated summary

Malaria parasites enter a phase of sexual reproduction involving gametocytes that rapidly develop into mature gametes for mating. This study used fluorescent labelling to track the process of DNA replication at both whole-cell and single-molecule levels. Several novel observations were made, including the identification of the Orc1 protein in gametocytes, the uncoupling of cytokinesis from DNA replication, and the distinct dynamics of DNA replication compared to asexual schizogony.