title: Involvement of phosphoinositide turnover in tracheary element differentiation in Zinnia elegans L. cells.
abstract: Mesophyll cells of Zinnia elegans L., cultured in the presence of phytohormones, will transdifferentiate and undergo programmed cell death to become tracheary elements, thick-walled cells of the xylem. This system is a model system for study of plant cell development and differentiation. We report that a high concentration of extracellular Ca(2+) is necessary during the first 6 h of culturing for tracheary elements to form. Extracellular Ca(2+) is still required at later times, but at a much lower concentration. When cells transdifferentiate in adequate Ca(2+), microsomal phospholipase C activity increases and levels of inositol 1,4,5-trisphosphate rise at about hour 4 of culturing. The production of inositol 1,4,5-trisphosphate appears to be important for tracheary element formation, since inhibitors of phospholipase C inhibit both inositol 1,4,5-trisphosphate production and tracheary element formation. Pertussis toxin, an inhibitor of GTP-binding proteins, inhibits transdifferentiation and eliminates inositol 1,4,5-trisphosphate production. Tracheary element formation was not completely abolished by inhibitors that eliminated inositol 1,4,5-trisphosphate production, suggesting the involvement of other pathways in regulating transdifferentiation.
authors.affiliation: Department of Molecular and Cell Biology, U-125, the University of Connecticut, Storrs, CT 06269-3125, USA.
authors.forename: Xianchao G
authors.initials: XG
authors.lastname: Zhang
authors.forename: Gary G
authors.initials: GG
authors.lastname: Coté
authors.forename: Richard C
authors.initials: RC
authors.lastname: Crain
mesh_terms: D019659:Asteraceae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D004963:Estrenes / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D018514:Plant Structures / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011760:Pyrrolidinones / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D004963:Estrenes; D010716:Phosphatidylinositols; D011760:Pyrrolidinones; D010566:Virulence Factors, Bordetella; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C084782:3-deoxy-3-fluoroinositol 1,4,5-trisphosphate; D015544:Inositol 1,4,5-Trisphosphate; D037342:Pertussis Toxin; D010738:Type C Phospholipases; D002118:Calcium