title: The MYB80 transcription factor is required for pollen development and the regulation of tapetal programmed cell death in Arabidopsis thaliana.
abstract: Arabidopsis thaliana MYB80 (formerly MYB103) is expressed in the tapetum and microspores between anther developmental stages 6 and 10. MYB80 encodes a MYB transcription factor that is essential for tapetal and pollen development. Using microarray analysis of anther mRNA, we identified 404 genes differentially expressed in the myb80 mutant. Employing the glucocorticoid receptor system, the expression of 79 genes was changed when MYB80 function was restored in the myb80 mutant following induction by dexamethasone. Thirty-two genes were analyzed using chromatin immunoprecipitation, and three were identified as direct targets of MYB80. The genes encode a glyoxal oxidase (GLOX1), a pectin methylesterase (VANGUARD1), and an A1 aspartic protease (UNDEAD). All three genes are expressed in the tapetum and microspores. Electrophoretic mobility shift assays confirmed that MYB80 binds to all three target promoters, with the preferential binding site containing the CCAACC motif. TUNEL assays showed that when UNDEAD expression was silenced using small interfering RNA, premature tapetal and pollen programmed cell death occurred, resembling the myb80 mutant phenotype. UNDEAD possesses a mitochondrial targeting signal and may hydrolyze an apoptosis-inducing protein(s) in mitochondria. The timing of tapetal programmed cell death is critical for pollen development, and the MYB80/UNDEAD system may regulate that timing.
authors.affiliation: Botany Department, La Trobe University, Melbourne, Victoria 3086, Australia.
authors.forename: Huy Anh
authors.initials: HA
authors.lastname: Phan
authors.forename: Sylvana
authors.initials: S
authors.lastname: Iacuone
authors.forename: Song F
authors.initials: SF
authors.lastname: Li
authors.forename: Roger W
authors.initials: RW
authors.lastname: Parish
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D016923:Cell Death / Q000502:physiology; D047369:Chromatin Immunoprecipitation; D035264:Flowers / Q000166:cytology* / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D011058:Pollen / Q000166:cytology / Q000254:growth & development*; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C119922:MYB103 protein, Arabidopsis; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D002265:Carboxylic Ester Hydrolases; C505423:VGD1 protein, Arabidopsis