Cancela Martín, Santos Guilherme B, Carmona Carlos, Ferreira Henrique B, Tort José Francisco, Zaha Arnaldo
Departamento de Biologia Molecular e Biotecnologia,Instituto de Biociências e Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS,Porto Alegre,Brazil.
Unidad de Biología Parasitaria,Instituto de Biología,Facultad de Ciencias,Universidad de la República, UDELAR,Montevideo,Uruguay.
Parasitology. 2015 Dec;142(14):1673-81. doi: 10.1017/S0031182015001134. Epub 2015 Oct 6.
Fasciola hepatica is the causative agent of fasciolosis, a zoonosis with significant impact both in human and animal health. Understanding the basic processes of parasite biology, especially those related to interactions with its host, will contribute to control F. hepatica infections and hence liver pathology. Mucins have been described as important mediators for parasite establishment within its host, due to their key roles in immune evasion. In F. hepatica, mucin expression is upregulated in the mammalian invasive newly excysted juvenile (NEJ) stage in comparison with the adult stage. Here, we performed sequencing of mucin cDNAs prepared from NEJ RNA, resulting in six different cDNAs clusters. The differences are due to the presence of a tandem repeated sequence of 66 bp encoded by different exons. Two groups of apomucins one with three and the other with four repeats, with 459 and 393 bp respectively, were identified. These cDNAs have open reading frames encoding Ser-Thr enriched proteins with an N-terminal signal peptide, characteristic of apomucin backbone. We cloned a 4470 bp gene comprising eight exons and seven introns that encodes all the cDNA variants identified in NEJs. By real time polymerase chain reaction and high-resolution melting approaches of individual flukes we infer that fhemuc-1 is a single-copy gene, with at least two different alleles. Our data suggest that both gene polymorphism and alternative splicing might account for apomucin variability in the fhemuc-1 gene that is upregulated in NEJ invasive stage. The relevance of this variation in host-parasite interplay is discussed.
肝片吸虫是肝片吸虫病的病原体，肝片吸虫病是一种人畜共患病，对人类和动物健康都有重大影响。了解寄生虫生物学的基本过程，尤其是那些与其宿主相互作用相关的过程，将有助于控制肝片吸虫感染，从而控制肝脏病理学。由于粘蛋白在免疫逃避中的关键作用，它们已被描述为寄生虫在其宿主体内定殖的重要介质。在肝片吸虫中，与成虫阶段相比，粘蛋白在哺乳动物侵袭性新脱囊幼虫（NEJ）阶段的表达上调。在这里，我们对从NEJ RNA制备的粘蛋白cDNA进行了测序，得到了六个不同的cDNA簇。差异是由于存在由不同外显子编码的66 bp串联重复序列。鉴定出两组脱辅基粘蛋白，一组有三个重复序列，另一组有四个重复序列，分别为459和393 bp。这些cDNA具有开放阅读框，编码富含丝氨酸-苏氨酸的蛋白质，带有N端信号肽，这是脱辅基粘蛋白骨架的特征。我们克隆了一个4470 bp的基因，该基因包含八个外显子和七个内含子，编码在NEJ中鉴定出的所有cDNA变体。通过对单个吸虫的实时聚合酶链反应和高分辨率熔解方法，我们推断fhemuc-1是一个单拷贝基因，至少有两个不同的等位基因。我们的数据表明，基因多态性和可变剪接可能是导致在NEJ侵袭阶段上调的fhemuc-1基因中脱辅基粘蛋白变异性的原因。本文讨论了这种变异在宿主-寄生虫相互作用中的相关性。
