Nucleotide sequence analysis of a transforming gene isolated from nasopharyngeal carcinoma cell line CNE2: an aberrant human immunoglobulin kappa light chain which lacks variable region.

A transforming gene, designated Tx, was isolated from a human nasopharyngeal carcinoma (NPC) cell line CNE2 by transfection and molecular cloning techniques. The Tx gene was analyzed using computer-based bioinformatics and compared with the known sequences in EMBL and GenBank databases. We found that Tx contains human immunoglobulin kappa light chain constant region, five intact joining regions J1-J5, five recombination signal sequences and an N-segment besides classic regulatory sequences such as TATA boxes, CAAT boxes, poly A signals, etc. Interestingly, Tx also contains several binding sites for nuclear transcription factors such as NF-kappaB, NF-IL6, TFIID, etc. In conclusion, there are only several base pairs mutations or deletions compared with normal Ig K JC gDNA fragment. In all, Tx is an aberrant human immunoglobulin kappa light chain that contains the constant region, five joining regions, which lacks the variable regions.