Differential Activation of Cellular DNA Damage Responses by Replication-Defective and Replication-Competent Adenovirus Mutants

作者：Prakash Anand; Jayaram Sumithra; Bridge Eileen^*

来源：Journal of Virology, 2012, 86(24): 13324-13333.

DOI：10.1128/JVI.01757-12

Adenovirus (Ad) mutants that lack early region 4 (E4) activate the phosphorylation of cellular DNA damage response proteins. In wild-type Ad type 5 (Ad5) infections, E1b and E4 proteins target the cellular DNA repair protein Mre11 for redistribution and degradation, thereby interfering with its ability to activate phosphorylation cascades important during DNA repair. The characteristics of Ad infection that activate cellular DNA repair processes are not yet well understood. We investigated the activation of DNA damage responses by a replication-defective Ad vector (AdRSV beta gal) that lacks E1 and fails to produce the immediate-early E1a protein. E1a is important for activating early gene expression from the other viral early transcription units, including E4. AdRSV beta gal can deliver its genome to the cell, but it is subsequently deficient for viral early gene expression and DNA replication. We studied the ability of AdRSV beta gal-infected cells to induce cellular DNA damage responses. AdRSV beta gal infection does activate formation of foci containing the Mdc1 protein. However, AdRSV beta gal fails to activate phosphorylation of the damage response proteins Nbs1 and Chk1. We found that viral DNA replication is important for Nbs1 phosphorylation, suggesting that this step in the viral life cycle may provide an important trigger for activating at least some DNA repair proteins.

• 出版日期2012-12