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Viêm gan virus (HAV), tác nhân gây bệnh của loại truyền nhiễm cấp tính, viêm gan A, là một sợi RNA virus tích cực phân loại trong Picornaviridae gia đình. Trong khi cả hai cấu trúc và tổ chức các tính năng chia sẻ bộ gen của nó trong phổ biến với các picornavirus khác | Section III Hepatitis A Virus Chapter 6 Structure and molecular virology Stanley M Lemon Annette Martin Introduction Hepatitis A virus HAV the causative agent of acute infectious type A hepatitis is a positive-strand RNA virus classified within the family Picornaviridae. While both its structure and the organization of its genome share features in common with other picornaviruses such as poliovirus or encephalomyocarditis virus several important features of HAV distinguish it from other human and animal members of this large virus family. These unique features of HAV include its relatively high level of resistance to thermal denaturation its remarkable stability under low pH conditions and the composition and details of the assembly of the viral capsid structure in as much as it is understood . Coupled with the fact that HAV shares only very limited nucleotide homology with other picornaviruses 1 these features have contributed to the classification of HAV within a novel genus of the family Picornaviridae the genus Hepatovirus.2 One other distinct species of picornavirus avian encephalomyelitis virus has been placed within this genus on the basis of a remarkably close phylogenetic relationship to HAV.3 Overview of HAV structure and the viral life-cycle As with other picornaviruses the infectious HAV particle is small non-enveloped and approximately 27 nm in diameter.4 It comprises a highly stable icosahedral protein capsid containing an RNA genome consisting of a single messenger-sense molecule approximately 7.5 kb in length.1 The HAV genome generally resembles that of other picornaviruses in terms of its overall organization and quite likely the mechanisms by which it replicates Figs 6.1 and 6.2 . There is a small viral protein VPg linked to the 5 terminus of the genomic RNA 5 and a lengthy templated poly-A tract at the 3 end. Like the genomic RNAs of other positive-strand viruses this positive-sense RNA acts as messenger RNA directing the translation of viral .
