CLONING OF A NEW ISOFORM OF A DNAJ PROTEIN FROM ALLIUM-PORRUM EPIDERMAL-CELLS

The cDNA of a DnaJ protein (called LdJ2) has been isolated from a libr ary of leek epidermal cells. A full-length clone was isolated. The cDN A contains 1511 bp and encodes for 418 amino acids. The encoded protei n is a DnaJ protein homologous to LdJ1. The C-terminal sequence of LdJ 2 is CAQQ, suggesting that this protein is farnesylated and is, theref ore, associated with the membranes. LdJ2 also contains a glycine-rich region and four Cys-x-x-Cys-x-Gly-x-Gly units. The function of these u nits (zinc fingers, or not), and the reason for the presence of severa l isoforms of the same DNAJ in the cell are discussed.