Kumar Krishan, Singal Ankita, Rizvi M Moshahid A, Chauhan Virander S
International Centre of Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067, India.
Parasitol Int. 2008 Jun;57(2):150-7. doi: 10.1016/j.parint.2007.11.005. Epub 2007 Dec 8.
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.
高迁移率族蛋白B1(HMGB1)是一种丰富的非组蛋白染色体结构蛋白,在不同物种间高度保守。已从疟原虫恶性疟原虫中鉴定并克隆出HMGB1的同源物。序列分析表明,恶性疟原虫HMGB1(PfHMGB1)与酿酒酵母、人类和小鼠的HMG盒蛋白分别具有45%、23%和18%的同源性,而PfHMGB2与它们的同源性分别为42%、21%和17%。疟原虫的PfHMGB1和PfHMGB2蛋白含有一个类似于哺乳动物HMGB1的B盒的HMG盒结构域。电泳迁移率变动分析(EMSA)表明,重组的PfHMGB1和PfHMGB2能与DNA结合。使用特异性抗体的免疫荧光分析显示,这些蛋白在环状体细胞核中大量表达。在滋养体和裂殖体阶段,疟原虫细胞质中也存在大量的PfHMGB1和PfHMGB2。通过逆转录PCR和ELISA分析发现,PfHMGB1和PfHMGB2都是小鼠腹腔巨噬细胞中促炎细胞因子如肿瘤坏死因子α的有效诱导剂。这些结果表明,分泌的PfHMGB1和PfHMGB2可能是引发/触发与疟疾感染相关的宿主炎症免疫反应的原因。