An Entamoeba cysteine peptidase specifically expressed during encystation
An Entamoeba cysteine peptidase specifically expressed during encystation
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DOI：
10.1016/j.parint.2008.07.002
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发表时间：
2008-12-01
影响因子：
1.9
通讯作者：
Bruchhaus, Iris
中科院分区：
文献类型：
--
作者：
Ebert, Frank;Bachmann, Anna;Bruchhaus, Iris
内阿米巴属的原生动物寄生虫拥有相当数量的半胱氨酸肽酶（CP），其中大多数分子对于阿米巴生物学的功能需要确定。为了确定 CP 是否在内阿米巴从滋养体到包囊的阶段转化过程中发挥作用，反之亦然，对爬行动物寄生虫内阿米巴入侵（一种用于研究内阿米巴包囊发育的模型生物）中 cp 基因的表达进行了分析。通过同源性搜索，在公共大肠杆菌基因组数据库中鉴定出 28 个木瓜蛋白酶样 cp 基因。对于其中八个基因，确定了阶段转换期间的表达谱。通过Northern印迹分析，eicp-a9、-b7、-b8和-c2的转录物分别在滋养体或包囊中以及在阶段转换期间分析的任何时间点均未检测到。另一方面，eicp-a5 在所有发育阶段都组成型表达，而 eicp-a3 和 eicp-a11 分别是滋养体特异性的。仅 eicp-b9 被发现具有包囊特异性，因为它仅在包囊诱导后 18 至 28 小时表达。通过相应蛋白 EiCP-B9 的免疫荧光显微镜证实了囊肿特异性表达。在未成熟的囊肿中，该分子位于囊肿壁附近聚集的结构中，但在成熟的囊肿中均匀分布。 EiCP-B9 在内阿米巴包囊过程中的精确功能仍有待确定。然而，自噬体内阿米巴标记的共定位研究表明，EiCP-B9 与内阿米巴自噬无关。 (c) 2008 Elsevier Ireland Ltd. 保留所有权利。
Protozoan parasites of the genus Entamoeba possess a considerable number of cysteine peptidases (CPs), the function of most of these molecules for amoeba biology needs to be established. In order to determine whether CPs may play a role during Entamoeba stage conversion from trophozoites into cysts and vice versa, expression of cp genes was analysed in the reptilian parasite Entamoeba invadens, a model organism for studying Entamoeba cyst development. By homology search, 28 papain-like cp genes were identified in public E invadens genome databases. For eight of these genes the expression profiles during stage conversion was determined. By Northern blot analysis, transcripts for eicp-a9, -b7, -b8 and -c2, respectively, were detected neither in trophozoites or cysts nor at any of the point of times analysed during stage conversion. On the other hand, eicp-a5 is constitutively expressed during all developmental stages, whereas eicp-a3 and eicp-a11, respectively, are trophozoite-specific. Only eicp-b9 was found to be cyst-specific as it is expressed exclusively 18 to 28 h after cyst induction. Cyst-specific expression was confirmed by immunofluorescence microscopy of the corresponding protein EiCP-B9. In immature cysts, the molecule is located in structures that accumulate near the cyst wall, but which are uniformly distributed in mature cysts. The precise function of EiCP-B9 during Entamoeba encystation remains to be determined. However, colocalisation studies with an Entamoeba marker for autophagosomes suggest that EiCP-B9 is not associated with Entamoeba autophagy. (c) 2008 Elsevier Ireland Ltd. All rights reserved.