Thymosin Beta 4, Y-Chromosomal (Tb4Y)

Lahn and Page (1997) isolated testis cDNAs encoding TB4Y, a Y-linked TB4X homolog. They identified TB4Y as 1 of 5 NRY genes that were expressed in many tissues and have homologs on the X chromosome that escape X inactivation.

The antigen, an 11-mer peptide (EVLLRPGLHFR), was encoded by a polymorphic region 405 bp upstream of the initiation codon of TMSB4Y. CTL precursor frequency analysis showed that approximately 25% of the total donor CTL responses in the patient 50 days after transplant were directed at this epitope, and the precursor was detectable almost 2 years after transplant. RT-PCR analysis detected wide expression of TMSB4Y mRNA in normal tissues, including hematopoietic cells, and TMSB4Y was also expressed in some leukemic cells.