The Ski oncoprotein interacts with Skip, the human homolog of Drosophila Bx42

The v-Ski avian retroviral oncogene is postulated to act as a transcription factor. Since protein-protein interactions have been shown to play an important role in the transcription process, we attempted to identify Ski protein partners with the yeast two-hybrid system. Using v-Ski sequence as bait, the human gene skip (Ski Interacting Protein) was identified as encoding a protein which interacts with both the cellular and viral forms of Ski in the two-hybrid system. Skip is highly homologous to the Drosophila melanogaster protein Bx42 which is found associated with chromatin in transcriptionally active puffs of salivary glands. The Ski-Skip interaction is potentially important in Ski's transforming activity since Skip was demonstrated to interact with a highly conserved region of Ski required for transforming activity. Like Ski, Skip is expressed in multiple tissue types and is localized to the cell nucleus.