Eimeria tenella microneme protein EtMIC4: capture of the full-length transcribed sequence and comparison with other microneme proteins
Eimeria tenella microneme protein EtMIC4: capture of the full-length transcribed sequence and comparison with other microneme proteins
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DOI：
10.1007/s00436-008-1301-0
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发表时间：
2009-02-01
影响因子：
2
通讯作者：
Tomley, Fiona M.
中科院分区：
文献类型：
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作者：
Periz, Javier;Ryan, Rachael;Tomley, Fiona M.
EtMIC4是柔嫩艾美耳虫的微粒蛋白，艾美耳虫是一种细胞内的顶端复合体原虫，可引起鸡的严重肠炎。EtMIC4基因已经被部分表征，在本研究中，我们使用cDNA末端快速扩增（5‘ race）和逆转录聚合酶链反应的组合策略来鉴定转录序列的真实5’端（登录号AJ306453.2）。将预测的EtMIC4转录起始位点与预测的EtMIC1、2和3基因起始位点进行比较，发现了类似的启动区，每个启动区都符合转录启动元件的共识序列。EtMIC4基因由11个外显子组成，对全长预测蛋白的分析发现了一个新的n端区域，该区域包括一个疏水信号肽，随后是四个血栓反应蛋白1型模块，这些模块与先前在蛋白质下游描述的相似。最佳拟合分析显示，EtMIC4与最大艾美球虫蛋白EmTFP250和预测的弓形虫微基因组蛋白TgMIC12具有高度同源性。EtMIC4和EmTFP250具有70%的氨基酸同源性，所有预测的结构域在两者之间都是保守的。EtMIC4和TgMIC12具有48%的同源性，它们具有非常相似的结构域组织和内含子/外显子边界的保守性。
EtMIC4 is a microneme protein of Eimeria tenella, an intracellular apicomplexan protozoan that can cause severe enteritis in chickens. The EtMIC4 gene has been partially characterised, and in this study, we used a combined strategy of rapid amplification of cDNA ends (5'RACE) and reverse transcription-polymerase chain reaction to identify the authentic 5' end of the transcribed sequence (accession number AJ306453.2). Comparison of the predicted EtMIC4 transcription start site with predicted start sites for EtMIC1, 2 and 3 genes identified comparable initiator regions that each conform to the consensus sequence for a transcriptional initiator element. The EtMIC4 gene is organised over 11 exons and analysis of the full-length predicted protein identified a new N-terminal region that comprises a hydrophobic signal peptide followed by four thrombospondin-type 1 modules that are similar to those previously described further downstream in the protein. Best-fit analysis shows that EtMIC4 shares high homology with the Eimeria maxima protein EmTFP250 and with TgMIC12, a predicted Toxoplasma gondii microneme protein. EtMIC4 and EmTFP250 share 70% amino acid identity and all predicted structural domains are conserved between the two. EtMIC4 and TgMIC12 share 48% identity and they have very similar domain organisation and conservation of intron/exon boundaries.