Coiled Coil Domain Containing Protein 26 (CCDC26)

Mapping of the retrovirus integration site revealed its insertion into the first intron of the CCDC26 gene, which they called RAM. The deduced 109-amino acid protein of predicted molecular mass 13.2 kD has an N-terminal signal sequence. EST database analysis indicated that RAM is expressed in bone marrow, spleen, testis, eye, heart, kidney, and skin, with prominent expression in embryo.9-cis RA extinguished RAM expression in the parental leukemia cell line but not in the WY-1 RA-resistant daughter cell line, suggesting that the retrovirus insertion in WY-1 cells enhanced and sustained RAM expression, leading to altered RA responsiveness. Knockdown of RAM by small interfering RNA (siRNA) did not activate cell differentiation or cell death on its own, but promoted 9-cis RA-induced differentiation and TRAIL-triggered apoptosis.