Pre-T-Cell Antigen Receptor Alpha (PTCRa)

PTCRA contains 4 exons with a first intron rich in repetitive Alu sequences and SINE and LINE elements. Analysis of the region 1.5 kb upstream of the ATG start codon detected no CAAT or TATA boxes or a potential promoter. However, the conserved 6.5-kb intron 1 contains binding sites for AP1 and for mu-EBP-C2. RT-PCR analysis identified a smaller splice variant, PT-alpha-2, encoding a 231-amino acid protein lacking a major part of the Ig-like domain, due to the elimination of exon 2. The deduced 282-amino acid type I transmembrane protein, 63% identical to the mouse protein, contains a leader sequence, an Ig constant domain-like extracellular region with a potential N-glycosylation site, a transmembrane region, and a 114-amino acid cytoplasmic tail with 3 potential phosphorylation sites.