title: ATHB23, an Arabidopsis class I homeodomain-leucine zipper gene, is expressed in the adaxial region of young leaves.
abstract: Homeobox genes are essential regulators of plant development. ATHB23, a class I homeodomain leucine zipper gene of Arabidopsis, was found to be induced by treatment with the phytohormone gibberellin (GA). In order to clarify its role in development, we performed a histochemical analysis of transgenic plants containing a construct with a GUS::GFP reporter under the control of the 1.5 kb upstream region of ATHB23. The construct was mainly expressed in young leaves and the styles of flowers but not in mature leaves. Microscopic examination of young leaves revealed that it was expressed in the adaxial domain of leaf primordia and the rib meristem. Expression of ATHB23, like that of GA5 encoding GA 20-oxidase, was reduced in mutants related to adaxial-abaxial leaf polarity (phb-1d, se-2, and kan1 kan2). Reduced expression of the GUS::GFP reporter gene was also observed in an se-2 background. These results indicate that ATHB23 is under the control of GA and other activators such as PHB, and is involved in establishing polarity during leaf development.
authors: Department of Biological Science, Sookmyung Women's University, Seoul 140-742, South Korea.
authors: Yun-Kyoung
authors: YK
authors: Kim
authors: Ora
authors: O
authors: Son
authors: Mi-Ran
authors: MR
authors: Kim
authors: Kyoung-Hee
authors: KH
authors: Nam
authors: Gyung-Tae
authors: GT
authors: Kim
authors: Myeong-Sok
authors: MS
authors: Lee
authors: Soon-Young
authors: SY
authors: Choi
authors: Choong-Ill
authors: CI
authors: Cheon
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000096:biosynthesis* / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005875:Gibberellins / Q000494:pharmacology; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics*; D016350:Leucine Zippers / Q000235:genetics*; D018519:Meristem / Q000378:metabolism; D009154:Mutation; D018515:Plant Leaves / Q000378:metabolism*
chemical_list: C523746:ATHB23 protein, Arabidopsis; D029681:Arabidopsis Proteins; D005875:Gibberellins; D018398:Homeodomain Proteins