Dantas Márcia Danielle A, Chavante Suely F, Teixeira Dárlio Inácio A, Lima João Paulo M S, Lanza Daniel C F
Laboratório de Biologia Molecular Aplicada, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil; Programa de Pós-Graduação em Bioquímica, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
Programa de Pós-Graduação em Bioquímica, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
Virus Res. 2015 May 4;203:66-71. doi: 10.1016/j.virusres.2015.03.015. Epub 2015 Apr 4.
Infectious myonecrosis virus (IMNV) has been the cause of many losses in shrimp farming since 2002, when the first myonecrosis outbreak was reported at Brazilian's northeast coast. Two additional genomes of Brazilian IMNV isolates collected in 2009 and 2013 were sequenced and analyzed in the present study. The sequencing revealed extra 643 bp and 22 bp, at 5' and 3' ends of IMNV genome respectively, confirming that its actual size is at least 8226 bp long. Considering these additional sequences in genome extremities, ORF1 can starts at nt 470, encoding a 1708 aa polyprotein. Computational predictions reveal two stem loops and two pseudoknots in the 5' end and a putative stem loop and a slippery motif located at 3' end, indicating that these regions can be involved in the start and termination of translation. Through a careful phylogenetic analysis, a higher genetic variability among Brazilian isolates could be observed, comparing with Indonesian IMNV isolates. It was also observed that the most variable region of IMNV genome is located in the first half of ORF1, coinciding with a region which probably encodes the capsid protrusions. The results presented here are a starting point to elucidate the viral's translational regulation and the mechanisms involved in virulence.
自2002年巴西东北海岸首次报告肌肉坏死疫情以来，传染性肌肉坏死病毒（IMNV）已成为虾类养殖中许多损失的原因。本研究对2009年和2013年收集的巴西IMNV分离株的另外两个基因组进行了测序和分析。测序结果显示，IMNV基因组的5'端和3'端分别额外有643 bp和22 bp，证实其实际长度至少为8226 bp。考虑到基因组末端的这些额外序列，ORF1可从第470个核苷酸开始，编码一个1708个氨基酸的多聚蛋白。计算预测显示，5'端有两个茎环和两个假结，3'端有一个假定的茎环和一个滑码基序，表明这些区域可能参与翻译的起始和终止。通过仔细的系统发育分析，与印度尼西亚IMNV分离株相比，可以观察到巴西分离株之间更高的遗传变异性。还观察到，IMNV基因组中变化最大的区域位于ORF1的前半部分，与可能编码衣壳突起的区域一致。本文给出的结果是阐明该病毒翻译调控及毒力相关机制的起点。
