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摘要
Nonoverlapping deletions that eliminated the 5' (HIV-1(U5/603del)), middle (HIV-1(U5/206del)), and 3' (HIV-1(U5/604del)) thirds of the U5 region of the human immunodeficiency virus type I (HIV-1) long terminal repeat (LTR) were studied for their effects on virus replication (transient transfection of HeLa cells) and infectivity (T-cell lines and peripheral blood mononuclear cells). All three mutants exhibited a wild-type phenotype in directing the production and release of virus particles from transfected HeLa cells. In infectivity assays, HIV-1(U5/206del) was usually indistinguishable from wild-type virus whereas HIV-1(U5/603del) was unable to infect human peripheral blood mononuclear cells or MT4 and CEM cells. Investigations of HIV-1(U5/603del) particles revealed a packaging defect resulting in a 10-fold reduction of encapsidated genomic RNA. The HIV-1(U5/604del) mutant either was noninfectious or exhibited delayed infection kinetics, depending on the cell type and multiplicity of infection. Quantitative competitive PCR indicated that HIV-1(U5/604del) synthesized normal amounts of viral DNA in newly infected cells. During the course of a long-term infectivity assay, a revertant of the HIV-1(U5/604del) mutant that displayed rapid infection kinetics emerged. Nucleotide sequence analysis indicated that the original 26-nucleotide deletion present in HIV-1(U5/604del) had been extended an additional 19 nucleotides in the revertant virus. Characterization of the HIV-1(U5/604del) mutant LTR in in vitro integration reactions revealed defective 3' processing and strand transfer activities that were partially restored when the revertant LTR substrate was used, suggesting that the reversion corrected a similar defect in the mutant virus.
- 出版日期1994-12
