期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 100, 期 7, 页码 4102-4107出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0730835100
关键词
-
资金
- NCI NIH HHS [R01 CA072649, CA72649] Funding Source: Medline
- NIAID NIH HHS [AI53362, R21 AI053362] Funding Source: Medline
- NIA NIH HHS [T32 AG00093, T32 AG000093] Funding Source: Medline
- NIGMS NIH HHS [GM21422, GM42554, R37 GM021422, R01 GM021422] Funding Source: Medline
The expression of activation-induced cytidine deaminase (AID) is prerequisite to a trifecta of key molecular events in B cells: class-switch recombination and somatic hypermutation in humans and mice and gene conversion in chickens. Although this critically important enzyme shares common sequence motifs with apolipoprotein B mRNA-editing enzyme, and exhibits deaminase activity on free deoxycytidine in solution, it has not been shown to act on either RNA or DNA. Recent mutagenesis data in Escherichia coli suggest that AID may deaminate dC on DNA, but its putative biochemical activities on either DNA or RNA remained a mystery. Here, we show that AID catalyzes deamination of dC residues on single-stranded DNA in vitro but not on double-stranded DNA, RNA-DNA hybrids, or RNA. Remarkably, it has no measurable deaminase activity on single-stranded DNA unless pretreated with RNase to remove inhibitory RNA bound to AID. AID catalyzes dC --> dU deamination activity most avidly on double-stranded DNA substrates containing a small transcription-like single-stranded DNA bubble, suggesting a targeting mechanism for this enigmatic enzyme during somatic hypermutation.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据