High mobility group box (HMGB) proteins of Plasmodium falciparum: DNA binding proteins with pro-inflammatory activity.
High mobility group box chromosomal protein 1 (HMGB1), known as an abundant, non-histone architectural chromosomal protein, is highly conserved across different species. Homologues of HMGB1 were identified and cloned from malaria parasite, Plasmodium falciparum. Sequence analyses showed that the P. falciparum HMGB1 (PfHMGB1) exhibits 45, 23 and 18%, while PfHMGB2 shares 42, 21 and 17% homology with Saccharomyces cerevisiae, human and mouse HMG box proteins respectively. Parasite PfHMGB1and PfHMGB2 proteins contain one HMG Box domain similar to B-Box of mammalian HMGB1. Electrophoretic Mobility Shift Assay (EMSA) showed that recombinant PfHMGB1 and PfHMGB2 bind to DNA. Immunofluorescence Assay using specific antibodies revealed that these proteins are expressed abundantly in the ring stage nuclei. Significant levels of PfHMGB1 and PfHMGB2 were also present in the parasite cytosol at trophozoite and schizont stages. Both, PfHMGB1 and PfHMGB2 were found to be potent inducers of pro-inflammatory cytokines such as TNFalpha from mouse peritoneal macrophages as analyzed by both reverse transcription PCR and by ELISA. These results suggest that secreted PfHMGB1 and PfHMGB2 may be responsible for eliciting/ triggering host inflammatory immune responses associated with malaria infection.
Kumar
Krishan
K
International Centre of Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067, India.
Singal
Ankita
A
Rizvi
M Moshahid A
MM
Chauhan
Virander S
VS
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D016207:Cytokines / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D024243:HMGB1 Protein / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D024261:HMGB2 Protein / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000276:immunology* / Q000469:parasitology*; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000378:metabolism; D016778:Malaria, Falciparum / Q000276:immunology / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010963:Plasmodium falciparum / Q000276:immunology* / Q000378:metabolism; D011817:Rabbits; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D016207:Cytokines; D004268:DNA-Binding Proteins; D024243:HMGB1 Protein; D024261:HMGB2 Protein; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse