The gene corresponding to this cDNA is designated AtPLC2. The overall structure of the predictedAtPLC2 protein is similar to those of plant PI-PLCsand mammalian δ-type PI-PLCs. Northern blotanalysis revealed that AtPLC2 is expressedconstitutively whereas AtPLC1S, another gene forPI-PLC of Arabidopsis, is induced byenvironmental stresses such as dehydration and salinity,indicating that the function of AtPLC2 isdistinct from that of AtPLC1S. The AtPLC2 mRNAwas detected in vegetative and floral tissues. Wedetermined the positions of these two PI-PLCs genes onArabidopsischromosomes by RFLP mapping using P1genomic clones.