ISOLATION OF THE MISSING 5'-END OF THE ENCODING REGION OF THE BOVINE LEUKEMIA-VIRUS CELL-RECEPTOR GENE

The missing 5'-end of the encoding region of the bovine leukemia virus (BLV) cell receptor gene (BLVRcp1/5') was isolated from a lambda gt11 cDNA library using the P-32-labeled EcoRI-Saml fragment corresponding to the 5'-end of a 2.3 kbp cDNA fragment encoding the binding domain of the bovine leukemia virus cell receptor gene (BLVRcp1). The nucleot ide and amino acid sequence analysis of the BLVRcp1/5' cDNA revealed t hat the 1058bp EcoRI fragment at its 5'-end contained a new 114 amino acid long sequence, and at its 3'-end contained a completely identical 88 amino acid overlapping region with the 5'-end of the BLVRcp1 cDNA. The combined sequences of both cDNAs represent the whole encoding reg ion of the BLV cell receptor gene. The longest open reading frame of t he BLV eel receptor gene encodes a protein containing 843 amino acids with a calculated molecular mass of 94.2 kDa which concurs with experi mentally detected native BLV receptor protein. Search for homology has shown that about 250bp of the BLV cell receptor gene is highly homolo gous to Venter's tag sequences of an unidentified gene from the human brain library.