Characterization of the human NTAK gene structure and distribution of the isoforms for rat NTAK mRNA

NTAK (neural- and thymus-derived activator for the ErbB kinase, neuregulin-2) is a novel member of the epidermal growth factor (EGF) family. We have isolated and characterized the human NTAK gene, comprising 12 exons spanning in excess of 55 kilobases (kb). The 7.0 kb long mRNA of the human NTAK gene was expressed in the human neuroblastoma SK–N–SH cell line with two alternative isoforms detected. Furthermore, six isoforms have been identified from rat brain and PC-12 cells. Although the α isoform of the NTAK gene was found to be expressed in all tissues including brain, the β isoform was expressed only in rat brain tissues. Potential regulatory regions included consensus binding sites for AP-2, TF-IIIA, Sp-1, and YY-1 located in the 5′-flanking region of the NTAK gene.