Sequence and gene structure of the hepatitis E virus isolated from Myanmar

Abstract

Hepatitis E virus (HEV) is a causative agent of enterically transmitted non-A, non-B hepatitis. Hepatitis E occurs not only in sporadic forms but also in epidemic outbreaks in the developing world. We have revealed the nucleotide and predicted amino acid sequences of full cDNA of HEV isolated from sporadic hepatitis E of Myanmar. The genome is 7194 nucleotides long, followed by a poly(A) tail, and has three open reading frames. The nonstructural gene is located in the 5' terminus, while the structural gene is situated in the 3' terminus. Our HEV strain has 98.5% nucleic acid identity with the HEV strain cloned by workers at Genelabs Incorporated from Myanmar. The difference is point nucleotide substitutions. There is a high degree of nucleotide relatedness among HEVs isolated from the same geographical location.

Sequence Comparison of the Capsid Region of Hepatitis E Viruses Isolated from Myanmar and China

“…Viral full-length cDNA was sequenced by Reyes and his colleagues (17), and by us as well (1). Their and our viruses originated from hepatitis E from Yangon (formerly called Rangoon) of Myanmar.…”

“…The 3'-terminal region of viral genome corresponds to structural or capsid protein (1,17) because it is rich in basic amino acids and contains at least two epitopes (12,20), which contributes to the immunodominant antigenic site. A sequence comparison of various HEV strains isolated from different geographical locations in this region may provide important information which will assist the development of a vaccine and molecular epidemiology.…”

Comparative characterization of antigenic epitopes in the immunodominant region of the protein encoded by open reading frame 3 in Burmese and Mexican strains of hepatitis E virus

“…Sequence comparisons have revealed two distinct HEV groups. The Mexican group, represented by only one HEV isolate, is somewhat different from the Burmese HEV group which is composed of several isolates Tsarev et al, 1992;Aye et al, 1993;Bi et aI., 1993). The primary structure of proteins encoded by all three ORFs is similar within the Burmese group with rare amino acid changes in proteins encoded by ORFs 2 and 3, whereas the polypeptide encoded by ORF 1 contains one hypervariable domain (Tsarev et al, 1992).…”

“…Hepatitis E virus (HEV) is an agent of enterically transmitted non-A, non-B hepatitis (ET-NANB) (Bradley, 1990;Reyes et al, 1990Reyes et al, , 1991a, which is a serious problem in many developing countries (Bradley, 1990;Wright, 1990). Recent success in cloning and sequencing of the HEV genome Tsarev et al, 1992;Aye et al, 1993) has allowed the elucidation of the genetic organization of this virus. Three open reading frames (ORFs) have been identified .…”

“…Several antigenic epitopes have been mapped in these proteins (Yarbough et al, 1991 ;Kaur et al, 1992;Khudyakov et al, 1993). The primary structure of the antigenic region located at the C terminus of the ORF 3 protein has been shown to be highly conserved within the Burmese group Tsarev et al, t992;Aye et al, 1993;Bi et al, 1993) and significantly different from the Mexican strain (Yarbough et al, 1991). Only 78 % sequence identity has been found between the C-terminal regions of ORF 3-encoded proteins of the HEV Burmese and Mexican strains (Yarbough et al, 1991).…”