Periodical
Extension of mismatched 3' termini of DNA is a major determinant of the infidelity of human immunodeficiency virus type 1 reverse transcriptase.
العنوان: | Extension of mismatched 3' termini of DNA is a major determinant of the infidelity of human immunodeficiency virus type 1 reverse transcriptase. |
---|---|
المؤلفون: | Perrino, F W, Preston, B D, Sandell, L L, Loeb, L A |
المصدر: | Proceedings of the National Academy of Sciences of the United States of America; November 1989, Vol. 86 Issue: 21 p8343-8347, 5p |
مستخلص: | The unusually high error rate of human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) suggests that polymerization errors by this enzyme contribute to the genetic variability of the AIDS virus. We have analyzed the mechanism for HIV-1 RT infidelity by studying two distinct steps that might lead to base substitution mutations: nucleotide misinsertions and elongation from 3'-terminal DNA mispairs. Our results indicate that the capacity of HIV-1 RT to polymerize nucleotides onto mispaired termini is a major factor in the production of mutations by this enzyme. When a noncomplementary dAMP was inserted opposite a template adenine by HIV-1 RT, the nascent 3'-terminal A.A mispair was readily extended by subsequent incorporation of the next complementary nucleotide. The frequencies of nucleotide addition onto 3'-terminal A-A, A-C, and A-G mispairs were determined by quantitating the amount of extended primers with a gel electrophoresis assay and by measuring mutagenesis after hybridization of mismatched primers opposite an amber mutation in bacteriophage phi X174 DNA. The mispair extension frequencies are approximately 50-fold higher by HIV-1 RT than by the mammalian replicative enzyme DNA polymerase alpha. |
قاعدة البيانات: | Supplemental Index |
تدمد: | 00278424 10916490 |
---|---|
DOI: | 10.1073/pnas.86.21.8343 |