title: ATML1 and PDF2 Play a Redundant and Essential Role in Arabidopsis Embryo Development.
abstract: The epidermis of shoot organs in plants develops from the outermost layer (L1) of the shoot apical meristem. In Arabidopsis, a pair of homeobox genes, ARABIDOPSIS THALIANA MERISTEM LAYER1 (ATML1) and PROTODERMAL FACTOR2 (PDF2), play a role in regulating the expression of L1-specific genes. atml1-1 pdf2-1 double mutants show striking defects in the differentiation of shoot epidermal cells. However, because atml1-1 and pdf2-1 have a T-DNA inserted downstream of the respective homeobox sequences, these alleles may not represent null mutations. Here we characterized additional mutant alleles that have a T-DNA insertion at different positions of each gene. Double mutants of a strong atml1-3 allele with each pdf2 allele were found to cause embryonic arrest at the globular stage. Although with low frequency, all double mutant combinations of a weak atml1-1 allele with each pdf2 allele germinated and showed phenotypes defective in shoot epidermal cell differentiation. We further confirmed that transgenic induction of PDF2 fused to the Drosophila Engrailed repressor domain temporarily interferes with epidermal cell differentiation in the wild-type background. These results indicate that ATML1 and PDF2 act redundantly as a positive regulator of shoot epidermal cell differentiation and at least one copy of these genes is essential for embryo development.
authors.affiliation: Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530 Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Ogawa
authors.affiliation: Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530 Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530 Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Sezaki
authors.affiliation: Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530 Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Kosaka
authors.affiliation: Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530 Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kondo
authors.affiliation: Department of Biological Science, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033 Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Kamata
authors.affiliation: Department of Biological Science, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033 Japan.
authors.forename: Mitsutomo
authors.initials: M
authors.lastname: Abe
authors.affiliation: Department of Biological Science, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033 Japan.
authors.forename: Yoshibumi
authors.initials: Y
authors.lastname: Komeda
authors.affiliation: Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530 Japan perfect@cc.okayama-u.ac.jp.
authors.forename: Taku
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D020090:Chromosome Segregation; D018548:Cotyledon / Q000235:genetics / Q000254:growth & development; D003433:Crosses, Genetic; D035264:Flowers / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018869:Heat-Shock Response / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D019441:Plant Epidermis / Q000166:cytology; D018515:Plant Leaves / Q000378:metabolism / Q000648:ultrastructure; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000254:growth & development; D012639:Seeds / Q000196:embryology* / Q000235:genetics / Q000648:ultrastructure
chemical_list: C103790:ATML1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; C472305:PDF2 protein, Arabidopsis; D012333:RNA, Messenger
keywords: ATML1; Arabidopsis thaliana; Embryo; Epidermis; HD-Zip IV; PDF2