InsP(3)-mediated calcium release induced by heterologous expression of total chicory Leaf RNA.
A calcium dependent-chloride current (I(ni)) was recorded in Xenopus oocytes injected with total RNA from chicory leaf tissues, following depolarization from -35 to +60 mV. However, the signal transduction mechanism mediating I(ni) is unknown. The development of this current was mimicked by intracellular injection of the second messenger InsP(3) in control (non-injected) oocytes. Moreover, InsP(3) injection after I(ni) rundown did not reinitiate the current. The same phenomenon was observed following a second injection into control oocytes. Measurement of InsP(3) production in injected oocytes showed a net increase in the InsP(3) level on depolarization. Moreover, extracellular application of caffeine (5 mM) significantly reduced the number of oocytes displaying I(ni). Also, extracellular application of U-73122, a potent PLC inhibitor, clearly reduced the occurrence of I(ni). These data provide the first evidence that the calcium homeostasis mechanism induced by heterologous expression of total RNA from chicory leaves involves the InsP(3) signaling pathway.
Debarbieux-Deleporte
M
M
Laboratoire de Physiologie Cellulaire, SN3, INSERM EMI 0228, Université des Sciences et Technologies de Lille, 59655 cedex, Villeneuve d'Ascq, France.
Delbreil
B
B
Collin
T
T
Delcourt
P
P
Vasseur
J
J
Prevarskaya
N
N
Ouadid-Ahidouch
H
H
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D018651:Cichorium intybus; D018118:Chloride Channels; D004594:Electrophysiology; D015544:Inositol 1,4,5-Trisphosphate / Q000502:physiology*; D008845:Microinjections; D009865:Oocytes; D018515:Plant Leaves / Q000235:genetics*; D018749:RNA, Plant / Q000096:biosynthesis / Q000302:isolation & purification / Q000502:physiology*; D015290:Second Messenger Systems / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism; D014982:Xenopus laevis
D018118:Chloride Channels; D018749:RNA, Plant; D015544:Inositol 1,4,5-Trisphosphate; D010738:Type C Phospholipases; D002118:Calcium