dc.description.abstract | Human enterovirus 71 (EV71) has been implicated in numerous epidemics of hand, foot, and mouth disease (HFMD). It belongs to the Enterovirus genus of the Picornaviridae family. The 5’ untranslated region (5’ UTR) of EV71 contains 744 nucleotides and functions as internal ribosome entry site (IRES). By directly recruiting ribosomes to the IRES (cap-independent translation), EV71 genome encodes a single polypeptide chain of 2194 amino acids which is later processed to yield eleven protein products. Previous studies have shown that a small yeast RNA, known as inhibitor RNA (IRNA), can block poliovirus and HCV IRES-mediated translation by binding the host protein factors which are necessary for IRES function. In our research, we examined the ability of the 5’UTR of EV71 to play as an IRES in yeast and thus to direct the synthesis of a reporter gene in a bicistronic vector. Unfortunately, EV71 IRES in promoterless vector can still trigger the expression of the reporter gene, suggesting that EV71 IRES has a cryptic promoter activity in yeast.
In the second part of this study, we further examined if there are interactions between these eleven viral proteins by yeast two hybrid system. In our study, viral protein 3A and 2B will form homomultimer respectively in order to participate in the interaction. Still, 3A can form heteromultimer with 2B and 2C. In addition, we found that only 2A inhibits the normal growth of yeast by toxicity test and that 2A may have certain transcription activation activity. | en_US |