TY - JOUR
T1 - HIV DNA is heavily uracilated, which protects it from autointegration
AU - Yan, Nan
AU - O'Day, Elizabeth
AU - Wheeler, Lee Adam
AU - Engelman, Alan
AU - Lieberman, Judy
PY - 2011/5/31
Y1 - 2011/5/31
N2 - Human immune cells infected by HIV naturally contain high uracil content, and HIV reverse transcriptase (RT) does not distinguish between dUTP and dTTP. Many DNA viruses and retroviruses encode a dUTPase or uracil-DNA glycosylase (UNG) to counteract uracil incorporation. However, although HIV virions are thought to contain cellular UNG2, replication of HIV produced in cells lacking UNG activity does not appear to be impaired. Here we show that HIV reverse transcripts generated in primary human immune cells are heavily uracilated (>500 uracils per 10 kb HIV genome). We find that HIV DNA uracilation, rather than being dangerous, may promote the early phase of the viral life cycle. Shortly after reverse transcription, the ends of the HIV DNA are activated by the viral integrase (IN) in preparation for chromosomal insertion. However, the activated ends can attack the viral DNA itself in a suicidal side pathway, called autointegration. We find here that uracilation of target DNA inhibits the strand transfer of HIV DNA ends by IN, thereby inhibiting autointegration and facilitating chromosomal integration and viral replication. When uracilation is increased by incubating uracil-poor cells in the presence of increasing concentrations of dUTP or by infecting with virus that contains the cytosine deaminase APOBEC3G (A3G), the proportion of reverse transcripts that undergo suicidal autointegration decreases. Thus, HIV tolerates, or even benefits from, nonmutagenic uracil incorporation during reverse transcription in human immune cells.
AB - Human immune cells infected by HIV naturally contain high uracil content, and HIV reverse transcriptase (RT) does not distinguish between dUTP and dTTP. Many DNA viruses and retroviruses encode a dUTPase or uracil-DNA glycosylase (UNG) to counteract uracil incorporation. However, although HIV virions are thought to contain cellular UNG2, replication of HIV produced in cells lacking UNG activity does not appear to be impaired. Here we show that HIV reverse transcripts generated in primary human immune cells are heavily uracilated (>500 uracils per 10 kb HIV genome). We find that HIV DNA uracilation, rather than being dangerous, may promote the early phase of the viral life cycle. Shortly after reverse transcription, the ends of the HIV DNA are activated by the viral integrase (IN) in preparation for chromosomal insertion. However, the activated ends can attack the viral DNA itself in a suicidal side pathway, called autointegration. We find here that uracilation of target DNA inhibits the strand transfer of HIV DNA ends by IN, thereby inhibiting autointegration and facilitating chromosomal integration and viral replication. When uracilation is increased by incubating uracil-poor cells in the presence of increasing concentrations of dUTP or by infecting with virus that contains the cytosine deaminase APOBEC3G (A3G), the proportion of reverse transcripts that undergo suicidal autointegration decreases. Thus, HIV tolerates, or even benefits from, nonmutagenic uracil incorporation during reverse transcription in human immune cells.
UR - http://www.scopus.com/inward/record.url?scp=79959350868&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79959350868&partnerID=8YFLogxK
U2 - 10.1073/pnas.1102943108
DO - 10.1073/pnas.1102943108
M3 - Article
C2 - 21576478
AN - SCOPUS:79959350868
SN - 0027-8424
VL - 108
SP - 9244
EP - 9249
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 22
ER -