Thymus High Mobility Group Box Protein 2 (TOX2)

TOX2 is a member of a subfamily of transcription factors that also includes TOX, TOX3, and TOX4 that share almost identical HMG-box DNA-binding domains which function to modify chromatin structure.The deduced rat protein contains 1 HMG box motif at its center, a nuclear localization signal at the N terminus, and 3 domains consisting of serine-rich, lysine-rich, and proline-rich regions, respectively. The sequence of the protein is 39% identical and 38% similar to the mouse and human TOX proteins, respectively. RT-PCR detected restricted expression of TOX2 in rat hypothalamus, pituitary gland, testis, uterus, and ovary, with highest expression in ovary. In situ hybridization analysis refined the location in the ovary to granulosa cells in early-stage follicles. Expression was very low in large antral follicles and the corpus luteum.