Coiled Coil Helix Coiled Coil Helix Domain Containing Protein 1 (CHCHD1)

CHCHD1 contains a central coiled-coil-helix-coiled-coil-helix (CHCH) domain. Each helix contains 2 cysteines separated by 9 amino acids. Human and mouse CHCHD1 share 85% amino acid identity in the conserved domain. RT-PCR detected strongest expression in first-trimester placental bed and in a choriocarcinoma cell line. Weak expression was detected in developing tissues, such as embryonic brain, chorionic villus fibroblasts, and full-term placenta. No expression was detected in adult tissues. In situ hybridization showed that expression in the first-trimester placental bed was restricted to proliferative cytotrophoblasts at the proximal zone of placental anchoring villi. Transfected choriocarcinoma cells expressed fluorescence-labeled CHCHD1 in the nucleus, and mutation analysis indicated that the nuclear localization domain is in the N terminus.