Phylogenesys and homology modeling in Zika virus epidemic: food for thought

<p>Zika virus (ZIKV) is an emerging Flavivirus that have recently caused an outbreak in Brazil and rapid spread in several countries. In this study, the consequences of ZIKV evolution on protein recognition by the host immune system have been analyzed. Evolutionary analysis was combined with homology modeling and T-B cells epitope predictions. Two separate clades, the African one with the Uganda sequence, as the most probable ancestor, and the second one containing all the most recent sequences from the equatorial belt were identified. Brazilian strains clustered all together and closely related to the French Polynesia isolates. A strong presence of a negatively selected site in the envelope gene (<i>Env</i>) protein was evidenced, suggesting a probable purging of deleterious polymorphisms in functionally important genes. Our results show relative conservancy of ZIKV sequences when envelope and other non-structural proteins (NS3 and NS5) are analyzed by homology modeling. However, some regions within the consensus sequence of NS5 protein and to a lesser extent in the envelope protein, show localized high mutation frequency corresponding to a considerable alteration in protein stability. In terms of viral immune escape, envelope protein is under a higher selective pressure than NS5 and NS3 proteins for HLA class I and II molecules. Moreover, envelope mutations that are not strictly related to T-cell immune responses are mostly located on the surface of the protein in putative B-cell epitopes, suggesting an important contribution of B cells in the immune response as well.</p

Additional file 1 of MISSEL: a method to identify a large number of small species-specific genomic subsequences and its application to viruses classification

The user guide for MISSEL software, which is a pdf file with all the instructions for the user to run the software. (PDF 891 KB

Epidemiological Data: Numbers of suspected ZIKV cases and suspected microcephaly cases per state and per epidemiological week.

Contains 1) CSV file with number suspected ZIKV cases from January 2015 to the end of December 2015; 2) CSV file with number of suspected microcephaly cases from January 2015 to the first week of January 2016. Numbers correspond to suspected microcephaly cases at week 20 of pregnancy; 3) CSV file with codes of state of residence and municipality of residence in Brazil; and 4) R scripts for correlation analysis described in SI Section 1.5

Sequence data details and alignments for dataset A and B.

Contains (1) table with accession numbers, isolate names, cell passage history, publication details, country/location of sampling, sampling dates and (2) Fasta format sequence alignments of datasets A and B

BEAST XML input file used for genetic analysis.

BEAST XML input file used to generate Figure 3 under a strict clock model, a Bayesian skyline coalescent prior and a CTMC prior on the clock rate