title: Evolution of general transcription factors.
abstract: Three genes GTF2IRD1, GTF2I, and GTF2IRD2, which encode members of the GTF2I (or TFII-I) family of so-called general transcription factors, were discovered and studied during the last two decades. Chromosome location and similarity of exon-intron structures suggest that the family evolved by duplications. The initial duplication of ancestral proto-GTF2IRD1 gene likely occurred in early vertebrates prior to origin of cartilaginous fish and led to formation of GTF2I (>450 MYA), which was later lost in bony fish but successfully evolved in the land vertebrates. The second duplication event, which created GTF2IRD2, occurred prior to major radiation events of eutherian mammalian evolution (>100 MYA). During recent steps of primate evolution there was another duplication which led to formation of GTF2IRD2B (<4 MYA). Two latest duplications were coupled with inversions. Genes belonging to the family have several highly conservative repeats which are implicated in DNA binding. Phylogenetic analysis of the repeats revealed a pattern of intragenic duplications, deletions and substitutions which led to diversification of the genes and proteins. Distribution of statistically rare atypical substitutions (p ≤ 0.01) sheds some light on structural differentiation of repeats and hence evolution of the genes. The atypical substitutions are often located on secondary structures joining α-helices and affect 3D arrangement of the protein globule. Such substitutions are commonly traced at the early stages of evolution in Tetrapoda, Amniota, and Mammalia.
authors.affiliation: Institute of Cytology and Genetics of Russian Academy of Sciences, Novosibirsk 90, Russia.
authors.forename: K V
authors.initials: KV
authors.lastname: Gunbin
authors.forename: A
authors.initials: A
authors.lastname: Ruvinsky
mesh_terms: D000818:Animals; D002875:Chromosomes / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005091:Exons; D005399:Fishes / Q000235:genetics; D017353:Gene Deletion; D020440:Gene Duplication; D006801:Humans; D007438:Introns; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D011323:Primates / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D035165:Transcription Factors, General / Q000235:genetics* / Q000378:metabolism; D019473:Transcription Factors, TFII / Q000235:genetics / Q000378:metabolism; D019474:Transcription Factors, TFIII; D014714:Vertebrates / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; C104259:GTF2I protein, human; C405493:GTF2IRD1 protein, human; C496282:GTF2IRD2 protein, human; D009124:Muscle Proteins; D009687:Nuclear Proteins; D015534:Trans-Activators; D035165:Transcription Factors, General; D019473:Transcription Factors, TFII; D019474:Transcription Factors, TFIII