Cellular transcription factor TFII-I represses adenovirus gene expression

Area of Science:

• Virology
• Molecular Biology
• Immunology

Background:

• Viruses, like human adenovirus (HAdV), must evade cellular antiviral defenses for replication.
• HAdV protein E4ORF3 counters these defenses by sequestering antiviral proteins and promoting degradation.
• TFII-I, a transcription factor, was identified as a target for E4ORF3-mediated degradation.

Purpose of the Study:

• To investigate the role of TFII-I in HAdV infection.
• To determine if TFII-I functions as a restriction factor against HAdV.
• To understand the timing of TFII-I's antiviral activity during the HAdV replication cycle.

Main Methods:

• Human adenovirus (HAdV) infection of cells with and without TFII-I.
• Quantification of infectious virus yield.
• Analysis of viral genome replication and gene/protein expression.

Main Results:

• TFII-I knockout (KO) significantly increased infectious HAdV yield.
• TFII-I KO led to increased viral genome replication and expression of early and late viral genes.
• TFII-I's antiviral function was observed early in the viral replication cycle.

Conclusions:

• TFII-I acts as a restriction factor against HAdV infection.
• TFII-I inhibits HAdV replication early in the viral life cycle.
• Understanding viral countermeasures like E4ORF3 is crucial for deciphering cellular antiviral mechanisms.