Transcriptional profile of the homologous recombination machinery and characterization of the EhRAD51 recombinase in response to DNA damage in Entamoeba histolytica

Abstract

Background: In eukaryotic and prokaryotic cells, homologous recombination is an accurate mechanism to generate genetic diversity, and it is also used to repair DNA double strand-breaks. RAD52 epistasis group genes involved in recombinational DNA repair, including mre11, rad50, nsb1/xrs2, rad51, rad51c/rad57, rad51b/rad55, rad51d, xrcc2, xrcc3, rad52, rad54, rad54b/rdh54 and rad59 genes, have been studied in human and yeast cells. Notably, the RAD51 recombinase catalyses strand transfer between a broken DNA and its undamaged homologous strand, to allow damaged region repair. In protozoan parasites, homologous recombination generating antigenic variation and genomic rearrangements is responsible for virulence variation and drug resistance. However, in Entamoeba histolytica the protozoan parasite responsible for human amoebiasis, DNA repair and homologous recombination mechanisms are still unknown.

UV irradiation responses in Giardia intestinalis

“…The mechanism of DNA repair by homologous recombination has also been studied in this parasite by inducing double stranded DNA breaks by UV-C treatment (Lopez-Casamichana et al, 2008). The RAD52 epistasis group of genes was shown to participate in DNA damaged response and the DNA damage was repaired by the homologous recombination pathway (Lopez-Casamichana et al, 2008). This is the major pathway used by lower eukaryotes, including protozoan parasites, to repair double stranded DNA damages (Bhattacharyya et al, 2004).…”

“…In E. histolytica, trophozoites subjected to UV-C treatment were studied using microarrays and the expression of genes encoding Fe-S clusters-containing proteins and DNA repair proteins were reported to be up-regulated, whereas genes associated to the cytoskeleton were repressed (Weber et al, 2009). The mechanism of DNA repair by homologous recombination has also been studied in this parasite by inducing double stranded DNA breaks by UV-C treatment (Lopez-Casamichana et al, 2008). The RAD52 epistasis group of genes was shown to participate in DNA damaged response and the DNA damage was repaired by the homologous recombination pathway (Lopez-Casamichana et al, 2008).…”

Proteomic analysis identifies endoribouclease EhL-PSP and EhRRP41 exosome protein as novel interactors of EhCAF1 deadenylase

“…For DNA damage induction, trophozoites (3.0 × 10 6 ) were irradiated with 254 nm UV-C at 150 J m −2 for 8 s using a UV-Stratalinker1800 device (Stratagene) as previously described [34]. Heat shock was done by incubating trophozoites at 42°C for 3 h as reported [35].…”

Characterization of the recombination activities of the Entamoeba histolytica Rad51 recombinase

“…It is conceivable that the ability of E. histolytica to go through diverse life stages, including genome duplications and spontaneous genome amplification, is likely mediated through HR [26–28]. In support of this argument, the E. histolytica genome contains genes homologous to the majority of the RAD52 epistasis group of genes [29–31]. The RAD52 epistasis group of genes accounts for the core DNA repair genes of HR ( RAD50, RAD51, RAD52, RAD54, RAD55, RAD57, RAD59, RDH54 , MRE11 , and XRS2 ), which are highly conserved among eukaryotes [32].…”

“…The RAD52 epistasis group of genes accounts for the core DNA repair genes of HR ( RAD50, RAD51, RAD52, RAD54, RAD55, RAD57, RAD59, RDH54 , MRE11 , and XRS2 ), which are highly conserved among eukaryotes [32]. In recent years, E. histolytica was shown to differentially express this group of genes in response to DNA damage [29,30], and HR was demonstrated in vivo [33]. Other protozoan parasites are reported to utilize HR as a means for adaptation and survival in host environments.…”