The transcription elongation complex directs activation-induced cytidine deaminase-mediated DNA deamination.
Activation-induced cytidine deaminase (AID) is a single-stranded DNA deaminase required for somatic hypermutation of immunoglobulin (Ig) genes, a key process in the development of adaptive immunity. Transcription provides a single-stranded DNA substrate for AID, both in vivo and in vitro. We present here an assay which can faithfully replicate all of the molecular features of the initiation of hypermutation of Ig genes in vivo. In this assay, which detects AID-mediated deamination in the context of transcription by Escherichia coli RNA polymerase, deamination targets either strand and declines in efficiency as the distance from the promoter increases. We show that AID binds DNA exposed by the transcribing polymerase, implicating the polymerase itself as the vehicle which distributes AID on DNA as it moves away from the promoter.
Besmer
Eva
E
Laboratory of Lymphocyte Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Market
Eleonora
E
Papavasiliou
F Nina
FN
D001483:Base Sequence; D003564:Cytidine Deaminase / Q000235:genetics* / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D003641:Deamination; D004926:Escherichia coli / Q000201:enzymology; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D014158:Transcription, Genetic; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
D004247:DNA; D012321:DNA-Directed RNA Polymerases; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D003564:Cytidine Deaminase