title: Spatial and temporal expression of the orchid floral homeotic gene DOMADS1 is mediated by its upstream regulatory regions.
abstract: The orchid floral homeotic gene, DOMADSI, is a marker gene specifically expressed in the transitional shoot apical meristem during floral transition in Dendrobium Madame Thong-In. DOMADSI is not detectable in vegetative tissues except a weak expression in the stem. Its transcript is uniformly localized in both of the inflorescence meristem and floral primordia, and later expressed in almost all of the floral organs. We isolated and sequenced a 3.5 kb DOMADSI promoter fragment upstream of the transcription start site, demonstrating the location of several putative DNA-binding sites, through which MADS-box and class I knox genes may modulate the DOMADSI expression. To gain insight into the molecular basis of the regulation of DOMADS1, deletion analysis of the DOMADSI::beta-glucuronidase (GUS) gene fusions was performed by means of the stable orchid transformation systems. The study shows that the full-length upstream promoter sequence confers the same spatial and temporal GUS staining pattern as that of the distribution of DOMADSI RNA during orchid development. We also identified the distinct cis-acting regulatory regions required for the control of DOMADS1 expression in vegetative and reproductive tissues, as well as the shoot apical meristem during floral transition.
authors: Department of Biological Sciences, Faculty of Science, National University of Singapore, Kent Ridge.
authors: Hao
authors: H
authors: Yu
authors: Shu Hua
authors: SH
authors: Yang
authors: Chong Jin
authors: CJ
authors: Goh
mesh_terms: D024506:5' Flanking Region / Q000235:genetics; D000595:Amino Acid Sequence; D001483:Base Sequence; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D029595:Orchidaceae / Q000235:genetics* / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics*; D018514:Plant Structures / Q000235:genetics* / Q000254:growth & development; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics* / Q000502:physiology; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion
chemical_list: D018744:DNA, Plant; D018398:Homeodomain Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D005966:Glucuronidase