title: An anthropoid-specific locus of orphan C to U RNA-editing enzymes on chromosome 22.
abstract: The cytidine (C) to uridine (U) editing of apolipoprotein (apo) B mRNA is mediated by tissue-specific, RNA-binding cytidine deaminase APOBEC1. APOBEC1 is structurally homologous to Escherichia coli cytidine deaminase (ECCDA), but has evolved specific features required for RNA substrate binding and editing. A signature sequence for APOBEC1 has been used to identify other members of this family. One of these genes, designated APOBEC2, is found on chromosome 6. Another gene corresponds to the activation-induced deaminase (AID) gene, which is located adjacent to APOBEC1 on chromosome 12. Seven additional genes, or pseudogenes (designated APOBEC3A to 3G), are arrayed in tandem on chromosome 22. Not present in rodents, this locus is apparently an anthropoid-specific expansion of the APOBEC family. The conclusion that these new genes encode orphan C to U RNA-editing enzymes of the APOBEC family comes from similarity in amino acid sequence with APOBEC1, conserved intron/exon organization, tissue-specific expression, homodimerization, and zinc and RNA binding similar to APOBEC1. Tissue-specific expression of these genes in a variety of cell lines, along with other evidence, suggests a role for these enzymes in growth or cell cycle control.
authors.affiliation: RNA Editing Group, MRC Clinical Sciences Centre, Imperial College, Hammersmith Hospital Campus, Du Cane Road, London, W12 ONN, UK.
authors.forename: Adam
authors.initials: A
authors.lastname: Jarmuz
authors.forename: Ann
authors.initials: A
authors.lastname: Chester
authors.forename: Jayne
authors.initials: J
authors.lastname: Bayliss
authors.forename: Jane
authors.initials: J
authors.lastname: Gisbourne
authors.forename: Ian
authors.initials: I
authors.lastname: Dunham
authors.forename: James
authors.initials: J
authors.lastname: Scott
authors.forename: Naveenan
authors.initials: N
authors.lastname: Navaratnam
mesh_terms: D000071479:APOBEC-1 Deaminase; D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D015152:Blotting, Northern; D020134:Catalytic Domain / Q000235:genetics; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D003564:Cytidine Deaminase / Q000235:genetics*; D005091:Exons / Q000235:genetics; D020224:Expressed Sequence Tags; D015894:Genome, Human; D000882:Haplorhini / Q000235:genetics; D006801:Humans; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D010802:Phylogeny; D017393:RNA Editing / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D016601:RNA-Binding Proteins; D000071479:APOBEC-1 Deaminase; C000605089:APOBEC1 protein, human; D003564:Cytidine Deaminase