AN ALTERNATIVE FORM OF POLY(ADP-RIBOSE) POLYMERASE IN DROSOPHILA-MELANOGASTER AND ITS ECTOPIC EXPRESSION IN RAT-1 CELLS

We here report an alternatively spliced form of PARP lacking exon 5 of the Drosophila PARP gene encoding the auto-modification domain. The a lternative form of PARP (PARP II) consists 804 amino acids with a mole cular weight of 92.3 kDa. The deduced amino acid sequence of PARP II w as completely matched to that of PARP I encoded by a full-length Droso phila PARP cDNA, except it lacks the region corresponding to the auto- modification domain. To examine the function of PARP II, stable transf ormants of Rat-1 cells in which PARP II was ectopically expressed by M MTV-LTR were isolated and characterized. After induction with dexameth asone, PARP II transformants showed slower growth and showed morpholog ical changes with loss of spindled shape compared to cells transformed with the vector or PARP I. The PARP II-transformed cells incorporated propidium iodide after induction; however, Annexin V and TUNEL analys is indicated these changes were not due to apoptosis. (C) 1998 Academi c Press.