Microcephaly protein ANKLE2 promotes Zika virus replication.

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Orthoflaviviruses, including Zika virus (ZIKV), replicate by interacting with host proteins.
• ZIKV is linked to severe congenital defects like microcephaly, involving the host protein ANKLE2.
• Previous work identified an interaction between ZIKV NS4A and ANKLE2, with NS4A inducing microcephaly dependent on ANKLE2.

Purpose of the Study:

• To investigate the role of ANKLE2 in ZIKV replication and understand its significance from a viral perspective.
• To determine if ANKLE2's role in ZIKV replication is conserved across different hosts and other orthoflaviviruses.

Main Methods:

• Examined ANKLE2 localization during ZIKV infection using microscopy.
• Assessed ZIKV replication in human and mosquito cell lines with ANKLE2 knockout or knockdown.
• Investigated the interaction of ANKLE2 with NS4A from multiple orthoflaviviruses.
• Analyzed innate immune activation and endoplasmic reticulum rearrangements in ANKLE2-deficient cells.

Main Results:

• ANKLE2 localized to sites of ZIKV NS4A accumulation during infection.
• ANKLE2 knockout in human cells significantly reduced ZIKV replication and innate immune activation.
• ANKLE2 knockdown in mosquito cells also decreased ZIKV replication.
• NS4A proteins from other orthoflaviviruses interacted with ANKLE2 and enhanced their replication.
• ANKLE2 knockout cells showed dysregulated virus-induced endoplasmic reticulum rearrangements.

Conclusions:

• ANKLE2 is a conserved host factor that promotes orthoflavivirus replication, likely by regulating membrane rearrangements for efficient replication and immune evasion.
• The interaction between ZIKV NS4A and ANKLE2 is crucial for viral replication.
• ANKLE2's essential role in developing tissues contributes to ZIKV's unique pathogenesis, causing microcephaly.