Malaria parasites utilize both homologous recombination and alternative end joining pathways to maintain genome...

Area of Science:

• Molecular Biology
• Genetics
• Parasitology

Background:

• Malaria parasites (Plasmodium falciparum) are haploid and susceptible to genomic instability from host immune responses and drugs.
• The parasite genome encodes homologous recombination (HR) machinery but lacks canonical non-homologous end joining (C-NHEJ) components for DNA double-strand break (DSB) repair.

Purpose of the Study:

• To investigate the mechanisms by which malaria parasites repair DSBs and maintain genomic integrity.
• To characterize the DNA repair pathways utilized by Plasmodium falciparum.

Main Methods:

• Development of an inducible, site-specific DSB generation system in Plasmodium falciparum using the yeast I-SceI endonuclease.
• Analysis of repaired genomic DNA to identify repair products and pathways.

Main Results:

• Plasmodium falciparum employs both a canonical HR pathway, leading to gene conversion, and an end joining (EJ) pathway for DSB repair.
• The EJ pathway produces limited, reproducible repair products, often with short insertions templated from surrounding sequences.
• Absence of C-NHEJ components suggests reliance on alternative repair mechanisms.

Conclusions:

• Malaria parasites possess distinct DNA repair pathways, including HR and an alternative EJ mechanism.
• This alternative end-joining pathway likely plays a primary role in repairing DSBs in Plasmodium falciparum, compensating for the lack of C-NHEJ.
• Understanding these repair pathways is critical for targeting malaria parasite genome integrity and developing novel therapeutics.