G to A hypermutation of TT virus.
APOBEC3 proteins function as part of innate antiviral immunity and induce G to A hypermutation in retroviruses and hepatitis B virus (HBV) genomes. Whether APOBEC3 proteins affect viruses that replicate without a reverse transcription step is unknown. TT virus (TTV), known to present in serum of healthy individuals and HBV carriers, has a single-stranded circular DNA genome and replicates without reverse transcription. In this study, we examined 67 blood samples obtained from healthy individuals and HBV carriers and observed G to A hypermutation of genomes of TTV in both healthy individuals and HBV carriers. During ALT flare-up in HBV carriers, G to A hypermutation of HBV increased, but TTV genomes significantly decreased in number and hypermutated TTV genomes became undetectable. Our results show that hypermutated TTV exist in healthy individuals and HBV carriers and that TTV genomes were susceptible to immune reaction directed to HBV by interacting with APOBEC3 proteins.
Tsuge
Masataka
M
Department of Medicine and Molecular Science, Division of Frontier Medical Science, Programs for Biomedical Research, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
Noguchi
Chiemi
C
Akiyama
Rie
R
Matsushita
Miyuki
M
Kunihiro
Kana
K
Tanaka
Sachi
S
Abe
Hiromi
H
Mitsui
Fukiko
F
Kitamura
Shosuke
S
Hatakeyama
Tsuyoshi
T
Kimura
Takashi
T
Miki
Daiki
D
Hiraga
Nobuhiko
N
Imamura
Michio
M
Takahashi
Shoichi
S
Hayses
C Nelson
CN
Chayama
Kazuaki
K
D000071478:APOBEC Deaminases; D000328:Adult; D001769:Blood / Q000821:virology; D003564:Cytidine Deaminase; D043525:Cytosine Deaminase / Q000276:immunology; D004279:DNA, Viral / Q000235:genetics*; D005260:Female; D006509:Hepatitis B / Q000821:virology; D006515:Hepatitis B virus / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D017354:Point Mutation; D022783:Torque teno virus / Q000235:genetics* / Q000302:isolation & purification
D004279:DNA, Viral; D043525:Cytosine Deaminase; D000071478:APOBEC Deaminases; C502889:APOBEC3 proteins, human; D003564:Cytidine Deaminase