title: Maize R2R3 Myb genes: Sequence analysis reveals amplification in the higher plants.
abstract: Transcription factors containing the Myb-homologous DNA-binding domain are widely found in eukaryotes. In plants, R2R3 Myb-domain proteins are involved in the control of form and metabolism. The Arabidopsis genome harbors >100 R2R3 Myb genes, but few have been found in monocots, animals, and fungi. Using RT-PCR from different maize organs, we cloned 480 fragments corresponding to a 42-44 residue-long sequence spanning the region between the conserved DNA-recognition helices (Myb(BRH)) of R2R3 Myb domains. We determined that maize expresses >80 different R2R3 Myb genes, and evolutionary distances among maize Myb(BRH) sequences indicate that most of the amplification of the R2R3 Myb gene family occurred after the origin of land plants but prior to the separation of monocots and dicots. In addition, evidence is provided for the very recent duplication of particular classes of R2R3 Myb genes in the grasses. Together, these findings render a novel line of evidence for the amplification of the R2R3 Myb gene family in the early history of land plants and suggest that maize provides a possible model system to examine the hypothesis that the expansion of Myb genes is associated with the regulation of novel plant cellular functions.
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Rabinowicz
authors.forename: E L
authors.initials: EL
authors.lastname: Braun
authors.forename: A D
authors.initials: AD
authors.lastname: Wolfe
authors.forename: B
authors.initials: B
authors.lastname: Bowen
authors.forename: E
authors.initials: E
authors.lastname: Grotewold
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D029681:Arabidopsis Proteins; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D005784:Gene Amplification / Q000235:genetics*; D020440:Gene Duplication; D017343:Genes, Plant / Q000235:genetics* / Q000502:physiology; D014644:Genetic Variation / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D018514:Plant Structures / Q000235:genetics; D020598:Proto-Oncogene Proteins c-myb; D016415:Sequence Alignment; D003313:Zea mays / Q000235:genetics*
chemical_list: C511988:ATR1 protein, Arabidopsis; D029681:Arabidopsis Proteins; C511989:CPC protein, Arabidopsis; D003062:Codon; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb