In cell culture , interference of __SP__ __NODE__ gene by siRNA increases neoplastic transformation of Imr 90 cells that involves a dominant negative protein fragment containing a oligomerization domain from __SP__ __NODE__ protein and a dominant negative protein fragment containing a oligomerization domain from __SP__ __NODE__ protein and oncogenic mutant __NODE__ protein ( X12V ) and __SP__ viral Small T antigen protein and __SP__ __NODE__ protein .