Transactivation potential of the C-terminus of human Nm23-H1.

The transactivation potential of Nm23-H1, a homolog of c-myc transcription factor Nm23-H2/PuF was assessed in yeast as a fusion protein with the DNA binding domains (DBDs) of GAL4 and LexA. The C-terminal half of Nm23-H1 exhibited strong transactivation of the reporter genes, LacZ and Leu2 carrying GAL4 and LexA upstream activating sequences (UASs), whereas the full-length Nm23-H1 and its N-terminal did not. Similar results were also obtained with Nm23-H2/PuF transactivating the reporter genes only by the C-terminus fused to GAL4 and LexA DBDs. Hence, our results suggested a possible regulatory role of the N-termini of Nm23 isotypes upon transactivation.