Growth of the protozoan parasite Entamoeba histolytica in 5-azacytidine has limited effects on parasite gene expression

Ali, Ibne Karim M.; Ehrenkaufer, Gretchen; Hackney, Jason A.; Singh, Upinder

doi:10.1186/1471-2164-8-7

Cited by 37 publications

(24 citation statements)

References 70 publications

(112 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This dual specificity of Ehmeth for DNA and tRNA has also been proposed for the Dnmt2 homolog in Drosophila melanogaster (10). Although control of gene expression by Ehmeth has been reported (6), this function is apparently not its most important function (11). Since Ehmeth expression fluctuates significantly (2-to 3-fold) between laboratory strains where its expression is barely detectable and strains isolated from patients, these fluctuations suggest that Ehmeth is associated with the parasite's adaptation to its host (reference 8 and unpublished observations).…”

Section: A Moebiasis Is a Parasitic Infection Of The Human Intestine mentioning

confidence: 99%

The Entamoeba histolytica Dnmt2 Homolog (Ehmeth) Confers Resistance to Nitrosative Stress

et al. 2014

View full text Add to dashboard Cite

c Nitric oxide (NO) has antimicrobial properties against many pathogens due to its reactivity as an S-nitrosylating agent. It inhibits many of the key enzymes that are involved in the metabolism and virulence of the parasite Entamoeba histolytica through S-nitrosylation of essential cysteine residues. Very little information is available on the mechanism of resistance to NO by pathogens in general and by this parasite in particular. Here, we report that exposure of the parasites to S-nitrosoglutathione (GSNO), an NO donor molecule, strongly reduces their viability and protein synthesis. However, the deleterious effects of NO were significantly reduced in trophozoites overexpressing Ehmeth, the cytosine-5 methyltransferase of the Dnmt2 family. Since these trophozoites also exhibited high levels of tRNA Asp methylation, the high levels suggested that Ehmeth-mediated tRNA Asp methylation is part of the resistance mechanism to NO. We previously reported that enolase, another glycolytic enzyme, binds to Ehmeth and inhibits its activity. We observed that the amount of Ehmeth-enolase complex was significantly reduced in GSNOtreated E. histolytica, which explains the aforementioned increase of tRNA methylation. Specifically, we demonstrated via sitedirected mutagenesis that cysteine residues 228 and 229 of Ehmeth are susceptible to S-nitrosylation and are crucial for Ehmeth binding to enolase and for Ehmeth-mediated resistance to NO. These results indicate that Ehmeth has a central role in the response of the parasite to NO, and they contribute to the growing evidence that NO is a regulator of epigenetic mechanisms.

show abstract

Section: A Moebiasis Is a Parasitic Infection Of The Human Intestine mentioning

confidence: 99%

The Entamoeba histolytica Dnmt2 Homolog (Ehmeth) Confers Resistance to Nitrosative Stress

et al. 2014

View full text Add to dashboard Cite

show abstract

“…However, a role for DNA methylation in protozoan parasites is relatively undefined. For example, in Entamoeba histolytica , blocking DNA methylation with the inhibitor 5-azacytidine affects the expression of only a small subset of genes (~2%) [9]. Additionally, some protozoan parasites such as Cryptosporidium parvum and Plasmodium falciparum contain DNA methyltransferase homologues but lack detectable DNA methylation [7, 10], which suggests that protozoal DNA methyltransferases may modify another target such as RNA.…”

mentioning

confidence: 99%

A map of 5-methylcytosine residues in Trypanosoma brucei tRNA revealed by sodium bisulfite sequencing

Militello¹,

Chen²,

Ackerman³

et al. 2014

Molecular and Biochemical Parasitology

View full text Add to dashboard Cite

In protozoan parasites, there is little information on the presence of covalent RNA modifications which comprise the epitranscriptome. Therefore, we determined if T. brucei tRNAAsp(GUC), tRNAGly(GCC), tRNAVal(AAC), and tRNATyr(GUA) contain 5-methylcytosines via RNA bisulfite sequencing. Most tRNAs examined have at least one 5-methylcytosine at the variable region-TψC junction. Only tRNAGly(GCC) displayed methylation of C40 in the anticodon stem, and there was partial methylation at this site. There is no evidence for methylation of C38 in the anticodon loop in the tRNAs analyzed. Analysis of tRNATyr(GUA) demonstrates that both unspliced and spliced molecules contain C48 methylation, indicating tRNA cytosine methylation can precede tRNA splicing. Overall, our data indicate that T. brucei tRNAs contain 5-methylcytosine residues in some, but potentially not all standard eukaryotic positions. The levels of cytosine methylation of different T. brucei tRNAs vary, suggesting the presence of a mechanism for methylation control.

show abstract

“…Two of the E. histolytica FDP-encoding genes have high transcript levels under basal conditions (EhFdp1 or 6.m00467, corresponding to the identical genes EHI_096710 and EHI_152650, and EhFdp2 or 155.m00084, corresponding to EHI_159860 [see Table S1 in the supplemental material]). These genes show no apparent modulation of transcript levels upon exposure to oxidative and nitrosative stresses (42), heat shock (44), the histone deacetylase inhibitor trichostatin A (11,16), or the DNA methyltransferase inhibitor 5-azacytidine (2) or in a mouse model of intestinal colonization and invasion (13). The gene that encodes E. histolytica FDP1 (EhFdp1; 6.m00467) displays higher transcript levels in E. histolytica than in the nonvirulent species E. dispar (24).…”

mentioning

confidence: 99%

A Detoxifying Oxygen Reductase in the Anaerobic Protozoan Entamoeba histolytica

et al. 2012

Self Cite

View full text Add to dashboard Cite

ABSTRACTWe report the characterization of a bacterial-type oxygen reductase abundant in the cytoplasm of the anaerobic protozoan parasiteEntamoeba histolytica. Upon host infection,E. histolyticais confronted with various oxygen tensions in the host intestine, as well as increased reactive oxygen and nitrogen species at the site of local tissue inflammation. Resistance to oxygen-derived stress thus plays an important role in the pathogenic potential ofE. histolytica. The genome ofE. histolyticahas four genes that encode flavodiiron proteins, which are bacterial-type oxygen or nitric oxide reductases and were likely acquired by lateral gene transfer from prokaryotes. TheEhFdp1gene has higher expression in virulent than in nonvirulentEntamoebastrains and species, hinting that the response to oxidative stress may be one correlate of virulence potential. We demonstrate that EhFdp1 is abundantly expressed in the cytoplasm ofE. histolyticaand that the protein levels are markedly increased (up to ∼5-fold) upon oxygen exposure. Additionally, we produced fully functional recombinant EhFdp1 and demonstrated that this enzyme is a specific and robust oxygen reductase but has poor nitric oxide reductase activity. This observation represents a new mechanism of oxygen resistance in the anaerobic protozoan pathogenE. histolytica.

show abstract

Growth of the protozoan parasite Entamoeba histolytica in 5-azacytidine has limited effects on parasite gene expression

Cited by 37 publications

References 70 publications

The Entamoeba histolytica Dnmt2 Homolog (Ehmeth) Confers Resistance to Nitrosative Stress

The Entamoeba histolytica Dnmt2 Homolog (Ehmeth) Confers Resistance to Nitrosative Stress

A map of 5-methylcytosine residues in Trypanosoma brucei tRNA revealed by sodium bisulfite sequencing

A Detoxifying Oxygen Reductase in the Anaerobic Protozoan Entamoeba histolytica

Contact Info

Product

Resources

About