Cloning and characterization of an autophagy-related gene, ATG12, from the three-host tick Haemaphysalis longicornis
Cloning and characterization of an autophagy-related gene, ATG12, from the three-host tick Haemaphysalis longicornis
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DOI：
10.1016/j.ibmb.2007.05.006
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发表时间：
2007-09-01
影响因子：
3.8
通讯作者：
Fujisaki, Kozo
中科院分区：
文献类型：
--
作者：
Umemiya, Rika;Matsuo, Tomohide;Fujisaki, Kozo
蜱是专性吸血性体外寄生虫，其生命周期的特征是饥饿期;许多蜱的生命中有95%以上是在宿主身上度过的。自噬是真核细胞中细胞质大量降解的过程，是由饥饿诱导的，对于延长生命至关重要。因此，我们假设自噬也发生在蜱中;然而，还没有关于蜱中自噬相关（ATG）基因的报道。在这里，我们显示了同源的ATG基因，ATG 12，和它的表达模式从若虫到成人阶段的三个主机蜱长角血蜱。序列分析表明，H.长角蚁ATG 12（HIA TG 12）cDNA全长649 bp，开放阅读框411 bp，编码136个氨基酸，羧基末端为甘氨酸残基，预测分子量为15.2 kDa。RT-PCR结果显示，HlATG 12在摄食初期表达下调，饱食后表达上调，蜕皮后表达再次下调。HlATG 12在充血后3个月表达水平最高。通过免疫电子显微镜，它表明，HlAtgl 2定位于周围的区域内的颗粒状结构内的中肠细胞的未进食的成年人。总之，HIA TG 12可能在未进食和蜕皮阶段发挥作用。(c)2007爱思唯尔有限公司保留所有权利。
Ticks are obligate hematophagous ectoparasites with a life cycle characterized by a period of starvation; many ticks spend more than 95% of their life off the host. Autophagy, which is the process of bulk cytoplasmic degradation in eukaryotic cells, is induced by starvation and is essential for extension of the lifespan. Therefore, we hypothesized that autophagy also occurs in ticks; however, there has been no report on autophagy-related (ATG) genes in ticks. Here, we show the homologue of an ATG gene, ATG12, and its expression pattern from the nympal to adult stages in the three-host tick Haemaphysalis longicornis. The sequence analysis showed that H. longicornis ATG12 (HIA TG12) cDNA is 649 bp, has a 411 bp ORF coding for a 136-amino acid polypeptide with the carboxy-terminal glycine residue, and has a predicted molecular mass of 15.2 kDa. Moreover, RT-PCR revealed that HlATG12 was downregulated at the beginning of feeding, upregulated after engorgement, and downregulated again after molting. The expression level of HlATG12 was highest at 3 months after engorgement. By immuno-electron microscopy, it was demonstrated that HlAtgl2 was localized to the region around granule-like structures within midgut cells of unfed adults. In conclusion, HIA TG12 might function during unfed and molting stages. (c) 2007 Elsevier Ltd. All rights reserved.