Project description:The E. histolytica transcription factor URE3-BP is a calcium-responsive regulator of two E. histolytica virulence genes, hgl5 and fdx1. URE3-BP was previously identified by a yeast one-hybrid screen of E. histolytica proteins capable of binding to the sequence TATTCTATT (URE3) in the promoter regions of hgl5 and fdx1. In this work precise definition of the consensus URE3 element was performed by electrophoretic mobility shift assays (EMSA) using base-substituted oligonucleotides, and the consensus motif validated using episomal reporter constructs. Transcriptome profiling of a strain induced to produce a dominant-positive URE3-BP was then used to identify additional genes regulated by URE3-BP. Fifty modulated transcripts were identified, and of these the EMSA defined motif T[atg]T[tc][cg]T[at][tgc][tg] was found in over half of the promoters (54% p<0.0001). Fifteen of the URE3-BP regulated genes were potential membrane proteins suggesting that one function of URE3-BP is to remodel the surface of E. histolytica in response to a calcium signal. Induction of URE3-BP lead to an increase in tranwell migration suggesting a possible role in the regulation of cellular motility.
Project description:The E. histolytica transcription factor URE3-BP is a calcium-responsive regulator of two E. histolytica virulence genes, hgl5 and fdx1. URE3-BP was previously identified by a yeast one-hybrid screen of E. histolytica proteins capable of binding to the sequence TATTCTATT (URE3) in the promoter regions of hgl5 and fdx1. In this work precise definition of the consensus URE3 element was performed by electrophoretic mobility shift assays (EMSA) using base-substituted oligonucleotides, and the consensus motif validated using episomal reporter constructs. Transcriptome profiling of a strain induced to produce a dominant-positive URE3-BP was then used to identify additional genes regulated by URE3-BP. Fifty modulated transcripts were identified, and of these the EMSA defined motif T[atg]T[tc][cg]T[at][tgc][tg] was found in over half of the promoters (54% p<0.0001). Fifteen of the URE3-BP regulated genes were potential membrane proteins suggesting that one function of URE3-BP is to remodel the surface of E. histolytica in response to a calcium signal. Induction of URE3-BP lead to an increase in tranwell migration suggesting a possible role in the regulation of cellular motility. 11 samples are used for two strains:EF and STOP at 0 and 9 hour time points
Project description:Differential expression was used to access gene differences after Entamoeba histolytica infection. Entamoeba histolytica is an important diarrheal pathogen worldwide, and induces apoptosis of the intestinal epithelium as part of its disease process. Regenerating (REG) 1 protein is anti-apoptotic. We investigated the involvement of REG 1 in E. histolytica colitis. Colonic biopsy samples were obtained from 8 subjects with acute E. histolytica colitis, and again 60 day later during convalescence. Gene expression in the human colon during acute and convalescent E. histolytica disease was evaluated using microarray and confirmed by polymerase chain reaction (PCR). REG 1 protein expression was evaluated with immunohistochemistry. The mechanism of REG 1 involvement in E. histolytica disease was subsequently investigated with a mouse model. REG 1A and REG 1B were the most upregulated genes in the human intestine in acute versus convalescent E. histolytica disease (p=0.003 and p=0.006 respectively). PCR confirmed the microarray results (p=<0.001 and p=0.001 respectively). Increased REG 1A and REG 1B protein expression was similarly observed by immunohistochemistry. REG 1 -/-mice were found to be significantly more susceptible to E. histolytica infection than wild type mice.
Project description:Up until now, the existence of Dnmt2-mediated DNA methylation has mostly been supported by focal analyses in organisms that contain Dnmt2, but no Dnmt1 or Dnmt3 DNA methyltransferase. In these organisms, several independent studies have also provided support for a biologically important function of Dnmt2-dependent DNA methylation. For example, Dnmt2-dependent methylation in Entamoeba histolytica, the causative agent of amebic dysentery, has been connected to the parasite s virulence. However, global DNA methylation levels in Entamoeba have been found to be very low. In addition, no specific features, such as CpG-specificity and specificity for certain genetic subcompartments have been described. This distinguishes Dnmt2-dependent methylation patterns from all other known methylomes and has raised questions about the validity of the underlying results. We have used whole-genome bisulfite sequencing for an unbiased characterization of the Entamoeba histolytica methylome at single-base resolution in a E.histolytica strain HM-1:IMSS devoid of significant level of EhDnmt2 (Ehmeth) expression. Paired-end BS-sequencing was performed on an Illumina Genome Analyzer with read lengths of 105 base pairs and an average insert size of 200 bp.