Translation of the first upstream ORF in the hepatitis B virus pregenomic RNA modulates translation at the core and polymerase initiation codons.
The human hepatitis B virus (HBV) has a compact genome encoding four major overlapping coding regions: the core, polymerase, surface and X. The polymerase initiation codon is preceded by the partially overlapping core and four or more upstream initiation codons. There is evidence that several mechanisms are used to enable the synthesis of the polymerase protein, including leaky scanning and ribosome reinitiation. We have examined the first AUG in the pregenomic RNA, it precedes that of the core. It initiates an uncharacterized short upstream open reading frame (uORF), highly conserved in all HBV subtypes, we designated the C0 ORF. This arrangement suggested that expression of the core and polymerase may be affected by this uORF. Initiation at the C0 ORF was confirmed in reporter constructs in transfected cells. The C0 ORF had an inhibitory role in downstream expression from the core initiation site in HepG2 cells and in vitro, but also stimulated reinitiation at the polymerase start when in an optimal context. Our results indicate that the C0 ORF is a determinant in balancing the synthesis of the core and polymerase proteins.
Chen
Augustine
A
Biochemistry Department, University of Otago Dunedin, New Zealand.
Kao
Y F
YF
Brown
Chris M
CM
D020121:5' Untranslated Regions; D001483:Base Sequence; D045744:Cell Line, Tumor; D018387:Codon, Initiator; D017124:Conserved Sequence; D015967:Gene Expression Regulation, Viral; D015684:Gene Products, pol / Q000235:genetics*; D017930:Genes, Reporter; D016679:Genome, Viral; D006512:Hepatitis B Core Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010442:Peptide Chain Initiation, Translational; D012367:RNA, Viral / Q000737:chemistry*
D020121:5' Untranslated Regions; D018387:Codon, Initiator; D015684:Gene Products, pol; D006512:Hepatitis B Core Antigens; C066027:P protein, Hepatitis B virus; D012367:RNA, Viral
Microbiol Mol Biol Rev. 2000 Mar;64(1):51-68
10704474
J Gen Virol. 1999 Jul;80 ( Pt 7):1769-76
10423146
Mol Cell Biol. 2000 Dec;20(23):8635-42
11073965
Gene. 2000 Dec 30;261(1):85-91
11164040
Bioinformatics. 2001 Oct;17(10):890-900
11673233
Trends Genet. 2001 Dec;17(12):685-7
11718907
J Biomol Struct Dyn. 2002 Feb;19(4):627-36
11843624
Mamm Genome. 2002 Aug;13(8):401-10
12226704
Science. 2002 Sep 13;297(5588):1864-7
12228716
Genes Dev. 2002 Nov 15;16(22):2906-22
12435632
Gene. 2002 Oct 16;299(1-2):1-34
12459250
Nucleic Acids Res. 2003 Jun 15;31(12):3174-84
12799445
Rev Med Virol. 2003 Jul-Aug;13(4):255-72
12820187
Mol Microbiol. 2003 Aug;49(4):859-67
12890013
Hepatology. 2003 Sep;38(3):545-53
12939579
Genes Dev. 2004 Jan 1;18(1):62-75
14701882
Nucleic Acids Res. 2004;32(4):1382-91
14990743
Biochem Soc Trans. 2004 Aug;32(Pt 4):592-6
15270684
Proc Natl Acad Sci U S A. 2004 Aug 3;101(31):11269-74
15277680
J Virol. 2004 Nov;78(21):11751-7
15479816
Cell. 1986 Jan 31;44(2):283-92
3943125
J Mol Biol. 1986 Jul 5;190(1):45-57
3023636
Annu Rev Biochem. 1987;56:651-93
3039907
Cell. 1989 Jan 13;56(1):85-92
2463093
J Cell Biol. 1989 Feb;108(2):229-41
2645293
J Biol Chem. 1989 Mar 25;264(9):5031-5
2538469
Proc Natl Acad Sci U S A. 1990 Jul;87(13):5158-62
1695011
J Virol. 1990 Sep;64(9):4578-81
2384923
Cell. 1990 Dec 21;63(6):1357-63
2261646
Virology. 1992 May;188(1):342-52
1566578
Gene Expr. 1991 May;1(2):117-25
1820209
J Virol. 1993 Aug;67(8):4886-95
7687304
J Bacteriol. 1994 Nov;176(22):7115-7
7961481
J Gen Virol. 1996 Jun;77 ( Pt 6):1123-7
8683196
Curr Biol. 1996 Mar 1;6(3):315-24
8805248
J Gen Virol. 1998 Sep;79 ( Pt 9):2181-9
9747727
Gene. 1999 Jul 8;234(2):187-208
10395892
Microbiol Mol Biol Rev. 2000 Jun;64(2):239-80
10839817