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.
Department of Medicine and Molecular Science, Division of Frontier Medical Science, Programs for Biomedical Research, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
Masataka
M
Tsuge
Chiemi
C
Noguchi
Rie
R
Akiyama
Miyuki
M
Matsushita
Kana
K
Kunihiro
Sachi
S
Tanaka
Hiromi
H
Abe
Fukiko
F
Mitsui
Shosuke
S
Kitamura
Tsuyoshi
T
Hatakeyama
Takashi
T
Kimura
Daiki
D
Miki
Nobuhiko
N
Hiraga
Michio
M
Imamura
Shoichi
S
Takahashi
C Nelson
CN
Hayses
Kazuaki
K
Chayama
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