Franzo Giovanni, Tucciarone Claudia Maria, Cecchinato Mattia, Drigo Michele
University of Padua, Legnaro, PD, Italy.
University of Padua, Legnaro, PD, Italy.
Mol Phylogenet Evol. 2017 Sep;114:82-92. doi: 10.1016/j.ympev.2017.05.019. Epub 2017 Jun 8.
Based on virus dependence from host cell machinery, their codon usage is expected to show a strong relation with the host one. Even if this association has been stated, especially for bacteria viruses, the linkage is considered to be less consistent for more complex organisms and a codon bias adaptation after host jump has never been proven. Canine parvovirus type 2 (CPV-2) was selected as a model because it represents a well characterized case of host jump, originating from Feline panleukopenia virus (FPV). The current study demonstrates that the adaptation to specific tissue and host codon bias affected CPV-2 evolution. Remarkably, FPV and CPV-2 showed a higher closeness toward the codon bias of the tissues they display the higher tropism for. Moreover, after the host jump, a clear and significant trend was evidenced toward a reduction in the distance between CPV-2 and the dog codon bias over time. This evidence was not confirmed for FPV, suggesting that an equilibrium has been reached during the prolonged virus-host co-evolution. Additionally, the presence of an intermediate pattern displayed by some strains infecting wild species suggests that these could have facilitated the host switch also by acting on codon bias.
基于病毒对宿主细胞机制的依赖性，预计它们的密码子使用情况会与宿主的密码子使用情况呈现出强烈的相关性。即便这种关联已经得到阐述，尤其是对于细菌病毒而言，但对于更复杂的生物体，这种联系被认为不那么一致，而且宿主转换后的密码子偏好适应性从未得到证实。犬细小病毒2型（CPV - 2）被选作模型，因为它代表了一个特征明确的宿主转换案例，其起源于猫泛白细胞减少症病毒（FPV）。当前的研究表明，对特定组织和宿主密码子偏好的适应影响了CPV - 2的进化。值得注意的是，FPV和CPV - 2对它们表现出更高嗜性的组织的密码子偏好显示出更高的相似性。此外，在宿主转换之后，随着时间的推移，CPV - 2与犬密码子偏好之间的距离呈现出明显且显著的缩小趋势。对于FPV，这一证据并未得到证实，这表明在长期的病毒 - 宿主共同进化过程中已经达到了一种平衡。此外，一些感染野生动物的毒株所呈现的中间模式表明，这些毒株也可能通过作用于密码子偏好促进了宿主转换。
