Carol A. Gilchrist

Ph.D. Biochemistry, University of Western Ontario

Research Interests

Regulation of virulence factors of Entamoeba histolytica; transcriptional control of Entamoeba histolytica

Current Projects

The early branching eukaryote Entamoeba histolytica is a human parasite that is the etiologic agent of amebic dysentery and liver abscess.  Only one of every 10 infections leads to disease and the parasite and host factors that control the outcome of infection are not well understood.  The mechanisms that control the changes from asymptomatic colonization to invasive amebiasis may involve changes in the expression of proteins involved in E. histolytica pathogenicity. There has been considerable divergence in the mechanisms of transcription of the early branching E. histolytica from later branching eukaryotes such as H. sapiens and S. cerevisiae. To increase our understanding of transcriptional regulation in this organism we investigated the mechanisms of transcriptional control of a well-characterized virulence protein, the galactose- and N-acetyl-D-galactosamine-inhibitable lectin (Gal/GalNAc-inhibitable lectin), which is essential for parasite adherence and contact-mediated cytolysis. The hgl5 gene of E. histolytica is negatively regulated through the URE3 DNA motif TATTCTATT. The E.histolytica URE3-BP protein was previously identified by virtue of its ability to bind to the upstream regulatory element 3 (URE3)sequence of the Gal/GalNAc lectin hgl5 gene. We are investigating the role of URE3-BP in E. histolytica calcium-dependent gene expression.

Selected Publications

Gilchrist CA, Leo M, Line CG, Mann BJ, Petri WA Jr. (2003) Calcium modulates promoter occupancy by the Entamoeba histolytica Ca2+-binding transcription factor URE3-BP. J Biol Chem. 278(7):4646-53. [Entrez]

Singh U, Gilchrist CA, Schaenman JM, Rogers JB, Hockensmith JW, Mann BJ, Petri WA. (2002)  Context-dependent roles of the Entamoeba histolytica core promoter element GAAC in transcriptional activation and protein complex assembly. Mol Biochem Parasitol . 120(1):107-16.  [Entrez]

 Ayeh-Kumi PF, Ali IM, Lockhart LA, Gilchrist CA, Petri WA Jr, Haque R. (2001) Entamoeba histolytica : genetic diversity of clinical isolates from Bangladesh as demonstrated by polymorphisms in the serine-rich gene. Exp Parasitol . 99(2):80-8. [Entrez]

Cheng XJ, Hughes MA, Huston CD, Loftus B, Gilchrist CA, Lockhart LA, Ghosh S, Miller-Sims V, Mann BJ, Petri WA Jr, Tachibana H. (2001) Intermediate subunit of the Gal/GalNAc lectin of Entamoeba histolytica is a member of a gene family containing multiple CXXC sequence motifs. Infect Immun . 69(9):5892-8. [Entrez]

Carol A. Gilchrist, Chris F. Holm, Molly A. Hughes, Joanna M. Schaenman, Barbara J. Mann, and William A. Petri Jr. (2001)  Identification and Characterization of an Entamoeba histolytica URE3 Sequence-Specific DNA Binding Protein Containing EF-Hand Motifs. J Biol Chem . 276(15):11838-43. [Entrez]

Joanna M. Schaenman, Carol A. Gilchrist, Barbara J. Mann and William A. Petri, Jr. (2001) Identification of Two E. histolytica Sequence-Specific Enhancer-Binding Proteins with Homology to the RNA-Binding Motif RRM.   J Biol Chem . 276(2):1602-9. [Entrez]

Gilchrist CA, Petri WA. Virulence factors of Entamoeba histolytica [Review].(1999) Current Opinion in Microbiology 2:433-437. [Entrez]

Gilchrist C A, Mann B, Petri W, Jr  (1998) Control of ferredoxin and Gal/GalNAc lectin gene expression in Entamoeba histolytica by a cis-acting DNA sequence. Infection and Immunity   66, 2383-2386. [Entrez]

Gilchrist C A, Purdy J, Mann B, Petri W, Jr  (1997) Control of Gene Expression in Entamoeba histolytica by a cis-Acting Upstream Regulatory Element. Archives of Medical Research 28, S39-S40. [Entrez]

Gilchrist C A, Purdy J, Mann B, Ackers J P, Hall R,  Petri W, Jr. (1997)  Recent developments in the transfection of Entamoeba histolytica. J Euk. Micro . 44(1), 24A.