title: DNA substrate length and surrounding sequence affect the activation-induced deaminase activity at cytidine.
abstract: Activation-induced deaminase (AID) is required for both immunoglobulin class switch recombination and somatic hypermutation. AID is known to deaminate cytidines in single-stranded DNA, but the relationship of this step to the class switch or somatic hypermutation processes is not entirely clear. We have studied the activity of a recombinant form of the mouse AID protein that was purified from a baculovirus expression system. We find that the length of the single-stranded DNA target is critical to the action of AID at the Cs positioned anywhere along the length of the DNA. The DNA sequence surrounding a given C influences AID deamination efficiency. AID preferentially deaminates Cs in the WRC motif, and additionally has a small but consistent preference for purine at the position after the WRC, thereby favoring WRCr (the lowercase r corresponds to the smaller impact on activity).
authors.affiliation: University of Southern California Norris Comprehensive Cancer Center, Department of Pathology, Los Angeles, California 90089, USA.
authors.forename: Kefei
authors.initials: K
authors.lastname: Yu
authors.forename: Feng-Ting
authors.initials: FT
authors.lastname: Huang
authors.forename: Michael R
authors.initials: MR
authors.lastname: Lieber
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D003564:Cytidine Deaminase / Q000737:chemistry* / Q000378:metabolism; D004247:DNA / Q000737:chemistry*; D051379:Mice; D009154:Mutation; D009841:Oligonucleotides / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D013379:Substrate Specificity; D013997:Time Factors; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
chemical_list: D009841:Oligonucleotides; D011994:Recombinant Proteins; D004247:DNA; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D003564:Cytidine Deaminase