Specificity
The isthmic organizer signals at the mid/hindbrain boundary (MHB) regulate the development and differentiation of the vertebrate caudal midbrain and the anterior hindbrain. The MHB forms at the boundary of expression between homeobox genes GBX2 and OTX2. GBX2 and OTX2 play distinct, essential roles in MHB positioning and development. During development, the GBX2 gene is expressed in the anterior hindbrain. Specifically, GBX2 negatively regulates OTX2 expression along the anterior-posterior axis; GBX2- mutants demonstrate an expanded OTX2 domain. During development, the GBX2 gene is expressed in the anterior hindbrain. GBX2 is expressed in the adult brain, spleen and female genital tract. The GBX2 gene is overexpressed in human prostate cancer cell lines (TSU-prl, PC3, DU145 and LNCaP). Furthermore, downregulation of GBX2 expression restricts tumorigenicity in human prostate cancer cell lines, which suggests that GBX2 expression may be required for growth of malignant prostate cells.
