Schwarz Ryan S, Fetterer Raymond H, Rosenberg George H, Miska Katarzyna B
Animal Parasitic Diseases Laboratory, U.S. Department of Agriculture, 10300 Baltimore Avenue, Beltsville, Maryland 20705, USA.
J Parasitol. 2010 Feb;96(1):49-57. doi: 10.1645/GE-2253.1.
With the Eimeria spp. populations that infect chickens used as a model for coccidian biology, we aimed to survey the transcriptome of Eimeria maxima and contrast it to the 2 other Eimeria spp. for which transcriptome data are available, i.e., Eimeria tenella and Eimeria acervulina . The asexual intracellular development stage, the merozoite, was specifically examined, and we used expressed sequence tag (EST) analysis to provide experimental evidence of transcription and a framework for understanding the merozoite stage of E. maxima . Of 2,680 individual ESTs obtained, 48.2% shared most significant (E < 10(-5)) homology to sequences from other apicomplexan species, primarily other Eimeria spp. and Toxoplasma gondii , and 47.5% were unique. Annotation of these ESTs enabled categorization to putative biological function and revealed an emphasis on translation, cytoskeleton, metabolism, signaling, transport, and protein folding, as well as the apicomplexan specific surface antigens and micronemes. Comparative analysis of abundantly expressed transcripts from merozoites of the 3 Eimeria spp. revealed a novel transcript common to all 3. Sharing no significant homology to any other sequence in public databases, this transcript was predicted to encode an Eimeria -specific protein (ESP) with 166-178 amino acids and 58.9-65.1% interspecific identity. A predicted signal peptide was identified, consistent with the assumption that ESP is a secreted protein. These annotated ESTs from E. maxima merozoites provide a resource for intra- and interspecific comparative analyses that will be useful in distinguishing the unique biology of coccidian parasites in relation to the diverse phylum of Apicomplexa.
以感染鸡的艾美耳球虫种群作为球虫生物学模型，我们旨在调查巨型艾美耳球虫的转录组，并将其与另外两种有转录组数据的艾美耳球虫，即柔嫩艾美耳球虫和堆型艾美耳球虫进行对比。我们专门研究了无性细胞内发育阶段，即裂殖子，并使用表达序列标签（EST）分析来提供转录的实验证据以及理解巨型艾美耳球虫裂殖子阶段的框架。在获得的2680个个体EST中，48.2%与其他顶复门物种的序列具有最高显著（E < 10(-5)）同源性，主要是其他艾美耳球虫物种和刚地弓形虫，47.5%是独特的。对这些EST的注释能够将其分类到推定的生物学功能，并揭示出对翻译、细胞骨架、代谢、信号传导、运输和蛋白质折叠以及顶复门特异性表面抗原和微线体的强调。对三种艾美耳球虫裂殖子中大量表达的转录本进行比较分析，发现了一种所有三种球虫共有的新转录本。该转录本与公共数据库中的任何其他序列均无显著同源性，预计编码一种含有166 - 178个氨基酸且种间同一性为58.9 - 65.1%的艾美耳球虫特异性蛋白（ESP）。鉴定出了一个预测的信号肽，这与ESP是一种分泌蛋白的假设一致。这些来自巨型艾美耳球虫裂殖子的注释EST为种内和种间比较分析提供了资源，这将有助于区分球虫寄生虫与顶复门不同门类相关的独特生物学特性。
