Involvement of phosphoinositide turnover in tracheary element differentiation in Zinnia elegans L. cells.
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.
Zhang
Xianchao G
XG
Department of Molecular and Cell Biology, U-125, the University of Connecticut, Storrs, CT 06269-3125, USA.
Coté
Gary G
GG
Crain
Richard C
RC
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
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