Transmembrane Protein 257 (TMEM257)

This intronless gene is expressed in the hippocampus and maps close to a candidate region for several X-linked mental retardation (XLMR) syndromes.It is conserved in primates, cow, and horse, but not found in mouse and rat. It is proposed to have an important function in the brain.

CXORF1 encodes a deduced 111-amino acid protein with putative protein kinase C phosphorylation sites at amino acids 77-79 and 96-98. Northern blot analysis detected 2 mRNA transcripts of 1.7 and 2.5 kb in brain and in the G361 melanoma cell line. In situ hybridization experiments showed that CXORF1 is expressed in all subfields of the hippocampus, with highest levels of expression in the dentate gyrus and CA3 region. Pyramidal neurons expressed a high level of CXORF1 mRNA, and glial cells expressed a modest level.