Abstract
Enterovirus type 71 (EV71) 2A protease exhibited strong transcriptional activity in yeast cells. The transcriptional activity of 2A protease was independent of its protease activity. EV71 2A protease retained its transcriptional activity after truncation of 40 amino acids at the N-terminus but lost this activity after truncation of 60 amino acids at the N-terminus or deletion of 20 amino acids at the C-terminus. Thus, the acidic domain at the C-terminus of this protein is essential for its transcriptional activity. Indeed, deletion of amino acids from 146 to 149 (EAME) in this acidic domain lost the transcriptional activity of EV71 2A protein though still retained its protease activity. EV71 2A protease was detected both in the cytoplasm and nucleus using confocal microscopy analysis. Coxsackie virus B3 2A protease also exhibited transcriptional activity in yeast cells. As expected, an acidic domain in the C-terminus of Coxsackie virus B3 2A protease was also identified. Truncation of this acidic domain resulted in the loss of transcriptional activity. Interestingly, this acidic region of poliovirus 2A protease is critical for viral RNA replication. The transcriptional activity of the EV71 or Coxsackie virus B3 2A protease should play a role in viral replication and/or pathogenesis.
Highlights
Enterovirus type 71 (EV71) is the causative agent of several human diseases, including hand-foot-and-mouth disease, encephalitis, and meningitis
EV71 2A protease exhibited strong transcriptional activity in yeast cells EV71 2A protease, when fused with the DNA-binding domain of Gal4, activates the reporter genes in yeast cells (Figure 1). This reaction is quite specific since none of the other proteins we studied at the same time exhibited this activity, including EV 71 3C protein, hepatitis C virus NS5A protein, NS3 protein(data not shown), or ARFP [7]
Deletion of 20 amino acids at the Cterminus of EV71 2A protease resulted in the loss of transcriptional activity (Figure 1)
Summary
Enterovirus type 71 (EV71) is the causative agent of several human diseases, including hand-foot-and-mouth disease, encephalitis, and meningitis. EV71 is a singlestranded, positive-sense RNA virus, which belongs to the Picornaviridae family [1]. Genomic RNA of picornaviruses (e.g. polioviruses) encodes a polyprotein precursor, which is processed by three proteases (the maturation protease, 2A protease, and the 3C protease) into at least 11 different proteins, which are arranged in the order of NH2-VP4-VP2-VP3-VP1-2A-2B-2C-3AVPg-3C-3D-COOH [1]. The 2A protease of poliovirus, a representative member of the Picornaviridae, is a cysteine protease with multiple functions [2]. Similar to poliovirus 2A protease, expression of EV71 2A protease led to cleavage of the eukaryotic initiation factor 4GI, a key factor for host protein synthesis [3,4]. Transient expression of EV71 2A protease alone resulted in the induction of apoptotic change [5,6]. The function of EV71 2A protease is not well
Published Version (Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have