Characterization of an Entamoeba histolytica high-mobility-group box protein induced during intestinal infection.
The unicellular eukaryote Entamoeba histolytica is a human parasite that causes amebic dysentery and liver abscess. A genome-wide analysis of gene expression modulated by intestinal colonization and invasion identified an upregulated transcript that encoded a putative high-mobility-group box (HMGB) protein, EhHMGB1. We tested if EhHMGB1 encoded a functional HMGB protein and determined its role in control of parasite gene expression. Recombinant EhHMGB1 was able to bend DNA in vitro, a characteristic of HMGB proteins. Core conserved residues required for DNA bending activity in other HMGB proteins were demonstrated by mutational analysis to be essential for EhHMGB1 activity. EhHMGB1 was also able to enhance the binding of human p53 to its cognate DNA sequence in vitro, which is expected for an HMGB1 protein. Confocal microscopy, using antibodies against the recombinant protein, confirmed its nuclear localization. Overexpression of EhHMGB1 in HM1:IMSS trophozoites led to modulation of 33 transcripts involved in a variety of cellular functions. Of these, 20 were also modulated at either day 1 or day 29 in the mouse model of intestinal amebiasis. Notably, four transcripts with known roles in virulence, including two encoding Gal/GalNAc lectin light chains, were modulated in response to EhHMGB1 overexpression. We concluded that EhHMGB1 was a bona fide HMGB protein with the capacity to recapitulate part of the modulation of parasite gene expression seen during adaptation to the host intestine.
Abhyankar
Mayuresh M
MM
Departments of Medicine, University of Virginia, Charlottesville, VA 22908-1340, USA.
Hochreiter
Amelia E
AE
Hershey
Jessica
J
Evans
Clive
C
Zhang
Yan
Y
Crasta
Oswald
O
Sobral
Bruno W S
BW
Mann
Barbara J
BJ
Petri
William A
WA
Gilchrist
Carol A
CA
D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004404:Dysentery, Amebic / Q000378:metabolism / Q000469:parasitology*; D004748:Entamoeba histolytica / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D024002:HMGB Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000469:parasitology*; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D011485:Protein Binding; D021381:Protein Transport; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D024002:HMGB Proteins; D015800:Protozoan Proteins; D016159:Tumor Suppressor Protein p53