title: A truncated MYB transcription factor from Antirrhinum majus regulates epidermal cell outgrowth.
abstract: Plant MYB genes can be divided into subgroups on the basis of additional conserved regions of sequence. In some cases, genes within a subgroup share similarities in function, as well as sequence. The functions of three proteins in subgroup 9 have been described, with AmMYBMX regulating the differentiation of conical-papillate petal epidermal cells, PhMYB1 involved in extending the growth of these cells, and AmMYBML1 involved in differentiation of several petal epidermal cell types. Here, the isolation of a gene encoding a new member of MYB subgroup 9, AmMYBML3 (Antirrhinum majus MYB MIXTA-LIKE 3) is described, which contains the defining regions of conserved sequence but is lacking the majority of the C-terminus, including the amphipathic alpha-helix presumed necessary for transcriptional activation. AmMYBML3 is expressed in all aerial organs, but its expression is restricted to outgrowing epidermal cells, including trichomes, stigmatic papillae, and petal conical-papillate cells. Ectopic expression of AmMYBML3 in tobacco results in the formation of conical-papillate cells in the usually flat carpel epidermis. These data suggest that this protein is capable of altering epidermal development, thus resulting in cellular outgrowth, despite the missing C-terminus, and may act in conjunction with other transcriptional activators to enhance cellular outgrowth from the epidermis of all aerial organs.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors.forename: Felix W
authors.initials: FW
authors.lastname: Jaffé
authors.forename: Alexander
authors.initials: A
authors.lastname: Tattersall
authors.forename: Beverley J
authors.initials: BJ
authors.lastname: Glover
mesh_terms: D032161:Antirrhinum / Q000166:cytology / Q000235:genetics*; D002454:Cell Differentiation; D002455:Cell Division / Q000235:genetics*; D017124:Conserved Sequence; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020570:Genes, myb; D015698:Genomic Library; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D018744:DNA, Plant; D018749:RNA, Plant; D014157:Transcription Factors