The Gbx family of transcription factors consists of two closely related proteins GBX1 and GBX2. A defining feature of the GBX family is a highly conserved 60 amino acid DNA-binding domain, which differs by just two amino acids.Gbx1andGbx2are co-expressed in several areas of the developing central nervous system including the forebrain, anterior hindbrain, and spinal cord, suggesting the potential for genetic redundancy. However, there is a spatiotemporal difference in expression ofGbx1andGbx2in the forebrain and spinal cord.Gbx2has been shown to play a critical role in positioning the midbrain/hindbrain boundary and developing anterior hindbrain, whereas gene-targeting experiments in mice have revealed an essential function forGbx1in the spinal cord for normal locomotion. To determine ifGbx2could potentially compensate for a loss ofGbx1in the developing spinal cord, we performed real-time PCR to examine levels ofGbx2expression inGbx1−/−spinal cord at embryonic day (E) 13.5, a developmental stage whenGbx2is rapidly downregulated. We demonstrate thatGbx2expression is elevated in the spinal cord ofGbx1−/−embryos.
