Molecular Cloning of Canine and Feline Flt3 Ligand Reveals High Degree of Similarity to the Human and Mouse Homologue But Uniquely Long Cytoplasmic Domain

The cDNAs encoding canine and feline flt3 ligand (FL) have been isolated from libraries constructed from canine or feline peripheral blood mononuclear cells and sequenced. A full-length canine FL cDNA encodes a polypeptide of 294 amino acids that shares 52.8% and 71.0% identity with the mouse and human FL protein, respectively. While the feline FL cDNA encodes a polypeptide of 291 amino acids that shares 54.170 and 70.2% identity with the mouse and human FL protein, respectively. The canine and feline FL proteins share 82.8% identity at amino acid level. Besides those encoding the full-length FL protein, several alternatively spliced forms of canine FL transcripts were also isolated. The canine and feline FL proteins have longer cytoplasmic domain than their mouse and human homologue.