title: Emerging role of the ubiquitin proteasome system in the control of shoot apical meristem function(f).
abstract: The shoot apical meristem (SAM) is a population of undifferentiated cells at the tip of the shoot axis that establishes early during plant embryogenesis and gives rise to all shoot organs throughout the plant's life. A plethora of different families of transcription factors (TFs) play a key role in establishing the equilibrium between cell differentiation and stem cell maintenance in the SAM. Fine tuning of these regulatory proteins is crucial for a proper and fast SAM response to environmental and hormonal cues, and for development progression. One effective way to rapidly inactivate TFs involves regulated proteolysis by the ubiquitin/26S proteasome system (UPS). However, a possible role of UPS-dependent protein degradation in the regulation of key SAM TFs has not been thoroughly investigated. Here, we summarize recent evidence supporting a role for the UPS in SAM maintenance and function. We integrate this survey with an in silico analysis of publicly-available microarray databases which identified ubiquitin ligases that are expressed in specific areas within the SAM, suggesting that they may regulate or act downstream of meristem-specific factors.
authors.affiliation: Istituto di Biologia e Biotecnologia Agraria, UOS Roma, Consiglio Nazionale delle Ricerche, Monterotondo Scalo, Roma 00015, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Di Giacomo
authors.forename: Giovanna
authors.initials: G
authors.lastname: Serino
authors.forename: Giovanna
authors.initials: G
authors.lastname: Frugis
mesh_terms: D018519:Meristem / Q000502:physiology*; D046988:Proteasome Endopeptidase Complex / Q000502:physiology*; D025801:Ubiquitin / Q000502:physiology*
chemical_list: D025801:Ubiquitin; D046988:Proteasome Endopeptidase Complex