| Summary: | 碩士 === 國立陽明大學 === 醫學生物技術暨檢驗學系暨研究所 === 98 === Enterovirus 71 (EV71), a member of the genus Enterovirus of the family Picornaviridae, is a common human pathogen associated with severe neurological manifestations including aseptic meningitis and poliomyelitis-like paralysis, and has caused several large outbreaks in Taiwan since 1998.
Translation of the enterovirus plus-strand RNA genome occurs via internal ribosomal entry site (IRES) at the 5’ untranslated region (5’-UTR). The IRES contains six secondary structure stem-loop domains. The initiation of IRES-dependent translation in some enteroviruses is modulated by certain cellular factors termed the IRES trans-acting factors (ITAFs) which bind the IRES stem-loop domains. Studies on the enteroviral ITAFs bind the IRES have mostly been limited to polioviruses and rhinoviruses, and the roles that these IRES stem-loop domains play in EV71 IRES-driven translation remains elusive.
In this study, we predicted six stem-loop domains in the EV71 IRES by the bioinformatic tool. The functional role of each stem-loop domain was dissected by developing a series of deletion mutants for assessing the IRES activity on a dual luciferase reporter system. Transient expression of the DNA and RNA versions of the deletion mutants as well as in vitro translation analysis were conducted. We found that while domain I appeared uninvolved in the IRES activity, the rest of the five domains are likely engaged in the IRES activity.
The results would enable us to gain insights into the functional domains in the EV71 IRES, a result that facilitates our understanding in the molecular mechanism of EV71 translation initiation.
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