Rahim Z, Raymond-Denise A, Sansonetti P, Guillen N
Unité de Pathogénie Microbienne Moléculaire, U 199 INSERM, Institut Pasteur, Paris, France.
Infect Immun. 1993 Mar;61(3):1048-54. doi: 10.1128/iai.61.3.1048-1054.1993.
To recognize myosin II in trophozoites of the human pathogen Entamoeba histolytica, a specific antimyosin polyclonal serum was raised against a fusion protein consisting of a 146-amino-acid fragment of the myosin II heavy chain A of E. histolytica (MhcA) fused with beta-galactosidase. The hybrid protein was encoded by a chimera gene formed by a DNA fragment, from the mhcA gene, amplified by polymerase chain reaction and fused with the lacZ gene of Escherichia coli. Polymerase chain reaction-amplified DNA is located within the region encoding the tail domain of myosin. This antibody recognized a 250-kDa protein in extracts of E. histolytica trophozoites. Confocal microscope analysis of antibody-labelled trophozoites indicated that MhcA localizes at the posterior pole of locomoting cells and concentrates within the uroid. These results might indicate that MhcA is involved in movement and in the uroid formation which help amoebas to escape the host immune response. These data are the first evidence indicating that myosin exists in E. histolytica. In addition, two other peptides were found in myosin-enriched extracts of amoebas, indicating that other myosins may be present in this parasite.
为了在人类病原体溶组织内阿米巴滋养体中识别肌球蛋白II，制备了一种针对融合蛋白的特异性抗肌球蛋白多克隆血清，该融合蛋白由溶组织内阿米巴肌球蛋白II重链A（MhcA）的146个氨基酸片段与β-半乳糖苷酶融合而成。该杂合蛋白由一个嵌合基因编码，该嵌合基因由通过聚合酶链反应扩增的来自mhcA基因的DNA片段与大肠杆菌的lacZ基因融合形成。聚合酶链反应扩增的DNA位于编码肌球蛋白尾部结构域的区域内。该抗体在溶组织内阿米巴滋养体提取物中识别出一种250 kDa的蛋白质。对抗体标记的滋养体进行共聚焦显微镜分析表明，MhcA定位于运动细胞的后极，并集中在尾状区。这些结果可能表明，MhcA参与运动和尾状区形成，这有助于变形虫逃避宿主免疫反应。这些数据是表明肌球蛋白存在于溶组织内阿米巴的首个证据。此外，在变形虫富含肌球蛋白的提取物中还发现了另外两种肽，表明该寄生虫中可能存在其他肌球蛋白。
