title: Regulation of the cell expansion gene RHD3 during Arabidopsis development.
abstract: The RHD3 (ROOT HAIR DEFECTIVE3) gene encodes a putative GTP-binding protein required for appropriate cell enlargement in Arabidopsis. To obtain insight into the mechanisms of RHD3 regulation, we conducted a molecular genetic dissection of RHD3 gene expression and function. Gene fusion and complementation studies show that the RHD3 gene is highly expressed throughout Arabidopsis development and is controlled by two major regulatory regions. One regulatory region is located between -1,500 and -600 bp upstream of the RHD3 gene and is required for vascular tissue expression. The other region is intragenically located and includes the 558-bp first intron, which is responsible for high-level expression of RHD3 throughout the plant. The presence and location of this intron is essential for gene function because constructs lacking this intron or constructs with the intron in an abnormal position are unable to functionally complement the rhd3 mutations. We also analyzed the role of other RHD genes and the plant hormones auxin and ethylene in RHD3 regulation, and we determined that these act downstream or independently from the RHD3 pathway. This study shows that multiple levels of regulation are employed to ensure the appropriate expression of RHD3 throughout Arabidopsis development.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Wang
authors.forename: Myeong Min
authors.initials: MM
authors.lastname: Lee
authors.forename: John W
authors.initials: JW
authors.lastname: Schiefelbein
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D005030:Ethylenes / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005816:Genetic Complementation Test; D007210:Indoleacetic Acids / Q000494:pharmacology; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D019441:Plant Epidermis / Q000254:growth & development; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D005030:Ethylenes; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; C036216:ethylene; D019204:GTP-Binding Proteins; C464507:RHD3 protein, Arabidopsis