Cytokine Like Protein 1 (CYTL1)

C17 is a cytokine-like protein specifically expressed in bone marrow and cord blood mononuclear cells that bear the CD34 surface marker. The deduced 136-amino acid protein has a calculated molecular mass of 17.2 kD. C17 contains an N-terminal secretory signal peptide and 4 alpha helices, a characteristic of hematopoietic cytokines and interleukins. Northern blot analysis detected a 1.0-kb transcript in adult bone marrow-derived CD34-positive cells. C17 expressed by transfected 293T cells migrated with an apparent molecular mass of about 26 kD on SDS/PAGE gels. A minor protein seen only in transfected cells migrated with an apparent molecular mass of about 40 kD. Digestion with glycosidases indicated that the unexpectedly high molecular mass was not due to glycosylation.