title: The Arabidopsis ARGOS-LIKE gene regulates cell expansion during organ growth.
abstract: Cell expansion, and its coordination with cell division, plays a critical role in the growth and development of plant organs. However, the genes controlling cell expansion during organogenesis are largely unknown. Here, we demonstrate that a novel Arabidopsis gene, ARGOS-LIKE (ARL), which has some sequence homology to the ARGOS gene, is involved in this process. Reduced expression or overexpression of ARL in Arabidopsis results in smaller or larger cotyledons and leaves as well as other lateral organs, respectively. Anatomical examination of cotyledons and leaves in ARL transgenic plants demonstrates that the alteration in size can be attributed to changes in cell size rather than cell number, indicating that ARL plays a role in cell expansion-dependent organ growth. ARL is upregulated by brassinosteroid (BR) and this induction is impaired in the BR-insensitive mutant bri1, but not in the BR-deficient mutant det2. Ectopic expression of ARL in bri1-119 partially restores cell growth in cotyledons and leaves. Our results suggest that ARL acts downstream of BRI1 and partially mediates BR-related cell expansion signals during organ growth.
authors.affiliation: Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604.
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Hu
authors.forename: Huay Mei
authors.initials: HM
authors.lastname: Poh
authors.forename: Nam-Hai
authors.initials: NH
authors.lastname: Chua
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D060406:Brassinosteroids; D049108:Cell Enlargement; D048429:Cell Size; D002777:Cholestanols; D018548:Cotyledon / Q000166:cytology / Q000254:growth & development; D015870:Gene Expression; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D010937:Plant Growth Regulators / Q000502:physiology; D018515:Plant Leaves / Q000166:cytology / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000166:cytology / Q000254:growth & development; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013260:Steroids, Heterocyclic; D015854:Up-Regulation
chemical_list: C479806:ARGOS protein, Arabidopsis; C513745:ARL protein, Arabidopsis; D029681:Arabidopsis Proteins; D060406:Brassinosteroids; D002777:Cholestanols; C098907:DET2 protein, Arabidopsis; D008565:Membrane Proteins; D010937:Plant Growth Regulators; D013260:Steroids, Heterocyclic; D011494:Protein Kinases; C108270:BRI1 protein, Arabidopsis; C023623:brassinolide