Cloning of a novel cdna from human placental library which is a new member of myl-like oncoproteins

Myl represents a family of more than fifty oncoproteins, implicated in the control of cell growth, development, and cellular differentiation. These nuclear proteins are involved in processes such as transcription, DNA repair, and site-specific recombination. A cysteine-rich (C3H, C4) zinc-finger binding domain (RING) is present in the N-terminal of these proteins. We have cloned a novel 3.6 kb cDNA from a human placenta! expression library. The clone has an open reading frame encoding a 89 kDa protein with 835 amino acids and an amino-terminal domain similar to the Myl protein. Our putative protein contains a cysteine-rich (C3H, C4) zinc-finger motif followed by two additional cysteine/histidine motifs which form distinct binding-domains characteristically present in TIF-1, RFP-ret, PMLRAR-A/B, and T18. The zinc-finger and the binding domains are followed immediately by a stretch of hydrophobic amino acids defining a heptad repeat of a putative coiled-coil structure which could provide an additional area for specific protein-protein interaction(s). The carboxy-terminal of the protein, shows a distinct coiled-coil motif, a prolinerich domain, and a glutamic/aspartic-rich acidic domain followed by an amphipathic coiled region. With our clone as a probe, Northern blot analyses of poly (A)⁺ RNA from human and rat tissues shows wide expression of an mRNA of about 3.0 kb.