Abstract
Meiosis depends on homologous recombination (HR) in most sexually reproducing organisms. Efficient meiotic HR requires the activity of the meiosis-specific recombinase, Dmc1. Previous work shows Dmc1 is expressed in Entamoeba histolytica, a eukaryotic parasite responsible for amoebiasis throughout the world, suggesting this organism undergoes meiosis. Here, we demonstrate Dmc1 protein is expressed in E. histolytica. We show that purified ehDmc1 forms presynaptic filaments and catalyzes ATP-dependent homologous DNA pairing and DNA strand exchange over at least several thousand base pairs. The DNA pairing and strand exchange activities are enhanced by the presence of calcium and the meiosis-specific recombination accessory factor, Hop2-Mnd1. In combination, calcium and Hop2-Mnd1 dramatically increase the rate of DNA strand exchange activity of ehDmc1. The biochemical system described herein provides a basis on which to better understand the role of ehDmc1 and other HR proteins in E. histolytica.
Highlights
In most eukaryotic organisms meiosis is essential for reproduction and comprises one round of DNA replication followed by two rounds of cell division to produce haploid gametes
Based on the crossreactivity of the scRad51 antibodies with hRAD51 and hDMC1, we reasoned the high sequence conservation (61%) between ehDmc1 and hDMC1 may be sufficient for the scRad51 antibodies to detect ehDmc1
Our results show two bands were detected in lysate from E. histolytica (Fig 1B, lane 3) that correspond to the same molecular weights of the purified ehRad51 and ehDmc1 (Fig 1B)
Summary
In most eukaryotic organisms meiosis is essential for reproduction and comprises one round of DNA replication followed by two rounds of cell division to produce haploid gametes. The Spo enzyme generates DNA double-strand breaks (DSBs) throughout the genome [1]. The newly formed DSBs are repaired through a DNA repair pathway known as homologous recombination (HR) [2], which forms physical connections between homologous. EhDmc Catalyzes D-Loop Formation and DNA Strand Exchange
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