Expression of a cDNA from apple encoding a homologue of DAD1, an inhibitorof programmed cell death

A cDNA library was constructed from developing fruit of apple (Malus domest ica Borkh.) fruit at two days after pollination. Differential screening for pollination-induced genes resulted in the isolation of MdDAD1, an apple ho mologue of genes for DAD1 (defender against cell death I). Southern hybridi sation suggests that apple contains at least two DAD1 homologues. In mammal s and Caenorhabditis elegans, DAD1 functions to protect cells against progr ammed cell death (PCD) (apoptosis). In apple we show that MdDAD1 transcript levels vary between tissues, and are induced during senescence of leaves, petals, and fruit, and also by flower pollination. In situ hybridisation sh owed that MdDAD1 mRNA was distributed primarily in the cells of vascular bu ndles. These results contrast with a constitutive pattern of expression rep orted for DAD1 in mammalian cells. (C) 1998 Elsevier Science Ireland Ltd. A ll rights reserved.