Banca de QUALIFICAÇÃO: JOANA LARISSA VICENTE DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : JOANA LARISSA VICENTE DA SILVA
DATE: 23/02/2026
TIME: 14:00
LOCAL: Centro de Biociências
TITLE:

PHYLOGENETIC ANALYSIS AND STRUCTURAL MUTATION CHARACTERIZATION OF THE CHIKUNGUNYA VIRUS IN RIO GRANDE DO NORTE (2022–2025)

 

KEY WORDS:

Chikungunya; molecular evolution; phylogeny; mutations; immunoinformatics; structural modeling.

PAGES: 40
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:

The Chikungunya virus (CHIKV), belonging to the family Togaviridae and the genus Alphavirus, is an arbovirus widely disseminated throughout Northeastern Brazil since its introduction in 2014, maintaining continuous circulation in the state of Rio Grande do Norte (RN). Given the scarcity of recent studies on viral genetic diversity in the state, this study aimed to genetically characterize CHIKV circulating in RN between 2022 and 2025, as well as to evaluate potential immunological implications and perform structural modeling of the main mutations identified. A total of 154 sequences of the E1 gene and 51 sequences of the structural polyprotein (E3–E2–6K–E1), obtained from public databases, were curated and analyzed through phylogenetic, mutational, immunoinformatic, and predictive structural modeling approaches. Phylogenetic analyses indicate that all samples belong to the East-Central-South African (ECSA) genotype, forming a consistent monophyletic cluster, suggesting possible local maintenance and ongoing endemic transmission. The sequences obtained for the year 2025 clustered into a cohesive subclade, indicating recent circulation of a regionally derived lineage. Mutation analysis identified ten substitutions primarily distributed across the E1 and E2 glycoproteins, with emphasis on A98T, frequently observed between 2022 and 2023; the K211T mutation, present in 2022, 2023, and 2025; I317T, characterized as an emerging mutation in 2025; and N214S, considered a transient mutation. Preliminary immunoinformatic analyses indicate that these mutations do not appear to substantially compromise the overall antigenicity of the structural proteins, preserving most predicted MHC class I and II epitopes. However, a qualitative shift in the MHC class I epitope repertoire was observed, with loss of epitopes present in the reference sequence and the acquisition of new epitopes in the mutants, in addition to a single loss of an MHC class II epitope. Structural modeling was used exclusively for spatial visualization of the mutations, allowing assessment of their distribution across the E1 and E2 glycoproteins and aiding preliminary interpretation of their relative positions in the viral structures. Overall, the findings to date indicate low structural diversification of CHIKV in Rio Grande do Norte and evolutionary maintenance of the ECSA lineage, with punctual mutations whose relevance will be further explored in subsequent analyses. The results reinforce the importance of continuous genomic surveillance and contribute to a better understanding of viral dynamics.

COMMITTEE MEMBERS:
Externo ao Programa - 2985070 - JONAS IVAN NOBRE OLIVEIRA - nullInterno - 348473 - JOSE VERISSIMO FERNANDES
Presidente - 1715230 - JOSELIO MARIA GALVAO DE ARAUJO