title: Regulation of CLV3 expression by two homeobox genes in Arabidopsis.
abstract: The ability of meristems to continuously produce new organs depends on the activity of their stem cell populations, which are located at the meristem tip. In Arabidopsis, the size of the stem cell domain is regulated by two antagonistic activities. The WUS (WUSCHEL) gene, encoding a homeodomain protein, promotes the formation and maintenance of stem cells. These stem cells express CLV3 (CLAVATA3), and signaling of CLV3 through the CLV1/CLV2 receptor complex restricts WUS activity. Homeostasis of the stem cell population may be achieved through feedback regulation, whereby changes in stem cell number result in corresponding changes in CLV3 expression levels, and adjustment of WUS expression via the CLV signal transduction pathway. We have analyzed whether expression of CLV3 is controlled by the activity of WUS or another homeobox gene, STM (SHOOT MERISTEMLESS), which is required for stem cell maintenance. We found that expression of CLV3 depends on WUS function only in the embryonic shoot meristem. At later developmental stages, WUS promotes the level of CLV3 expression, together with STM. Within a meristem, competence to respond to WUS activity by expressing CLV3 is restricted to the meristem apex.
authors.affiliation: Institut für Entwicklungsbiologie der Universität zu Köln, Gyrhofstrasse 17, D-50931 Köln, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Brand
authors.forename: Margit
authors.initials: M
authors.lastname: Grünewald
authors.forename: Martin
authors.initials: M
authors.lastname: Hobe
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Simon
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005801:Genes, Homeobox; D017930:Genes, Reporter / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D018519:Meristem / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics*; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development; D017346:Protein Serine-Threonine Kinases; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics
chemical_list: C118167:AT2G27250 protein, Arabidopsis; D029681:Arabidopsis Proteins; C401621:CLV2 protein, Arabidopsis; D018398:Homeodomain Proteins; D008565:Membrane Proteins; D010940:Plant Proteins; C097496:STM protein, Arabidopsis; C116421:WUSCHEL protein, Arabidopsis; D020794:Receptor Protein-Tyrosine Kinases; C118166:CLV1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases