title: Retroposition and evolution of the DNA-binding motifs of YY1, YY2 and REX1.
abstract: YY1 is a DNA-binding transcription factor found in both vertebrates and invertebrates. Database searches identified 62 YY1 related sequences from all the available genome sequences ranging from flying insects to human. These sequences are characterized by high levels of sequence conservation, ranging from 66% to 100% similarity, in the zinc finger DNA-binding domain of the predicted proteins. Phylogenetic analyses uncovered duplication events of YY1 in several different lineages, including flies, fish and mammals. Retroposition is responsible for generating one duplicate in flies, PHOL from PHO, and two duplicates in placental mammals, YY2 and Reduced Expression 1 (REX1) from YY1. DNA-binding motif studies have demonstrated that YY2 still binds to the same consensus sequence as YY1 but with much lower affinity. In contrast, REX1 binds to DNA motifs divergent from YY1, but the binding motifs of REX1 and YY1 share some similarity at their core regions (5'-CCAT-3'). This suggests that the two duplicates, YY2 and REX1, although generated through similar retroposition events have undergone different selection schemes to adapt to new roles in placental mammals. Overall, the conservation of YY2 and REX1 in all placental mammals predicts that each duplicate has co-evolved with some unique features of eutherian mammals.
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA. jkim@lsu.edu
authors.forename: Jeong Do
authors.initials: JD
authors.lastname: Kim
authors.forename: Christopher
authors.initials: C
authors.lastname: Faulk
authors.forename: Joomyeong
authors.initials: J
authors.lastname: Kim
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D004175:Diptera / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D019143:Evolution, Molecular; D020440:Gene Duplication; D023281:Genomics; D006801:Humans; D007448:Invertebrates / Q000235:genetics; D051741:Kruppel-Like Transcription Factors / Q000737:chemistry; D008322:Mammals / Q000235:genetics; D008969:Molecular Sequence Data; D018626:Retroelements; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry; D014714:Vertebrates / Q000235:genetics; D050986:YY1 Transcription Factor / Q000737:chemistry* / Q000145:classification / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D051741:Kruppel-Like Transcription Factors; D018626:Retroelements; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494698:YY1 protein, human; C506066:YY2 protein, human; C507976:ZFP42 protein, human