Cloning a cDNA from human NK/T cells which codes for an unusual leucine zipper containing protein

A 1724 base pair (bp) clone, B3-1, was obtained from a human NK subtracted cDNA library and sequenced. The cDNA encoded a 324 amino acid protein with a calculated molecular mass of 36 kDa. The deduced protein did not contain any hydrophobic domains, suggesting that it was not secreted or membrane bound. Extensive database searches showed no significant overall homology to any known proteins or genes. The protein did, however, contain an unusually long (twice normal) leucine zipper and the nuclear targeting sequence found in many transcription factors and oncogenes. The cDNA also contained three repeats of the sequence 'ATTTA' in its 3' untranslated region, a motif associated with many oncogenes, transcription factors and interleukins. The mRNA for this gene is weakly expressed in resting NK/T cells.