A gene encoding a phosphatidylinositol-specific phospholipase C is induced by dehydration and salt stress in Arabidopsis thaliana.
A cDNA corresponding to a putative phosphatidylinositol-specific phospholipase C (PI-PLC) in the higher plant Arabidopsis thaliana was cloned by use of the polymerase chain reaction. The cDNA, designated cAtPLC1, encodes a putative polypeptide of 561 aa with a calculated molecular mass of 64 kDa. The putative product includes so-called X and Y domains found in all PI-PLCs identified to date. In mammalian cells, there are three types of PI-PLC, PLC-beta, -gamma, and -delta. The overall structure of the putative AtPLC1 protein is most similar to that of PLC-delta, although the AtPLC1 protein is much smaller than PLCs from other organisms. The recombinant AtPLC1 protein synthesized in Escherichia coli was able to hydrolyze phosphatidylinositol 4,5-bisphosphate and this activity was completely dependent on Ca2+, as observed also for mammalian PI-PLCs. These results suggest that the AtPLC1 gene encodes a genuine PI-PLC of a higher plant. Northern blot analysis showed that the AtPLC1 gene is expressed at very low levels in the plant under normal conditions but is induced to a significant extent under various environmental stresses, such as dehydration, salinity, and low temperature. These observations suggest that AtPLC1 might be involved in the signal-transduction pathways of environmental stresses and that an increase in the level of AtPLC1 might amplify the signal, in a manner that contributes to the adaptation of the plant to these stresses.
Hirayama
T
T
Laboratory of Plant Molecular Biology, Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Japan.
Ohto
C
C
Mizoguchi
T
T
Shinozaki
K
K
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D017931:DNA Primers; D018076:DNA, Complementary; D005612:Freeze Drying; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006982:Hypertonic Solutions; D008322:Mammals; D008969:Molecular Sequence Data; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000096:biosynthesis* / Q000235:genetics; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D018076:DNA, Complementary; D006982:Hypertonic Solutions; D011993:Recombinant Fusion Proteins; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase