Subcellular localization of Zika virus during infection in human cells

Author(s)

Roberta Maraninchi Silveira

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2018-06-28

Examining board members

Luis Lamberti Pinto da Silva; Eurico de Arruda Neto; Luiz Tadeu Moraes Figueiredo; Luciana Barros de Arruda Hinds

• Advisor: Luis Lamberti Pinto da Silva

Abstract

Zika virus (ZIKV) is an arbovirus of the Flaviviridae family, of the genus Flavivirus that is transmitted by Aedes mosquitoes. Despite its emerging importance in public health, little is known about the molecular mechanisms involved in the replicative cycle of ZIKV in human cells. Thus, the general objective of this study was to characterize the subcellular distribution of the ZIKV in the host cell and to elucidate cellular factors that regulate the intracellular trafficking of proteins involved in these processes. More specifically, to determine the cellular compartments that serve as assembly platforms for the ZIKV. In addition, the study aimed to verify if the functioning of the Endosomal Sorting Complexes Required for Transport (ESCRT) machinery is required in the replicative cycle of ZIKV. In order to identify the subcellular localization of ZIKV, different intracellular markers were used, and, according to the results, it was demonstrated that at 3 hours post infection (h. p. i.) ZIKV proteins colocalize with an early endosome marker, whereas within 15h p.i. it is already possible to detect newlysynthesized viral proteins in the endoplasmic reticulum (ER). Subsequently, within 27h p.i., the ZIKV is directed to the Golgi complex. Together, these results delineate the targeting of ZIKV proteins through the secretory pathway over time. In addition, the involvement of the ESCRT machinery was tested by knocking down the expression of ESCRT-I protein TSG101 in ZIKV-infected cells. The results obtained suggest that ESCRT-I plays an important role in ZIKV replication, with viral titers decreasing when TSG101 levels are depleted in the cell. Together, the results allow us to conclude that ZIKV is associated with the initial secretory pathways (RE and Golgi complex) throughout the infection, and that the ESCRT-I TSG101 protein plays an important role in viral replication. Thus, this study contributes to a better understanding of the dynamics of ZIKV replication in human cells. (AU)

• FAPESP's process: 16/05945-1 - Mechanisms involved in the assembly and externalization of Zika virus in human cells.
• Grantee: Roberta Maraninchi Silveira
• Support Opportunities: Scholarships in Brazil - Master