Oligomer synthesis by priming deficient polymerase in hepatitis B virus core particle.
Hepadnavirus DNA polymerase functions in DNA synthesis and encapsidation, and acts as a primer for minus-strand DNA synthesis. Through protein priming reaction, a short DNA oligomer synthesized from the bulge of epsilon as template is covalently attached to the Tyr residue in the terminal protein (TP) domain of DNA polymerase. Using endogenous polymerase assays and native agarose gel analysis, we detected endogenous polymerase activity in priming-deficient mutant core particles, but not in reverse transcriptase (RT) reaction- or P protein-deficient mutant core particles. In addition, priming-deficient mutant core particles incorporated radiolabeled (32)P-dATP, (32)P-TTP, and (32)P-dGTP, but not (32)P-dCTP. Our results suggest that the priming-deficient mutant P protein has the ability to synthesize oligomers (presumably nascent minus-strand DNA) in the absence of covalent linkage between TP and the first deoxynucleotide. We propose that the priming-deficient mutant may be defective in minus-strand DNA translocation to direct repeat (DR) 1 at the 3' end of pregenomic RNA (pgRNA) that leads to the elongation of minus-strand DNA.
Kim
Hee-Young
HY
Department of Microbiology, Ajou University School of Medicine, Suwon 442-721, South Korea.
Park
Gil-Soon
GS
Kim
Eung-Goo
EG
Kang
Seung-Hyun
SH
Shin
Ho-Joon
HJ
Park
Sun
S
Kim
Kyongmin Hwang
KH
D004277:DNA, Single-Stranded / Q000096:biosynthesis; D004279:DNA, Viral / Q000096:biosynthesis; D015684:Gene Products, pol / Q000172:deficiency / Q000378:metabolism*; D006515:Hepatitis B virus / Q000378:metabolism*; D009842:Oligopeptides / Q000096:biosynthesis*; D012194:RNA-Directed DNA Polymerase / Q000172:deficiency / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D014779:Virus Replication
D004277:DNA, Single-Stranded; D004279:DNA, Viral; D015684:Gene Products, pol; D009842:Oligopeptides; C066027:P protein, Hepatitis B virus; D012194:RNA-Directed DNA Polymerase