Characterization of ectopically-expressed ets1 in human colon-cancer cells - induction of putative ets1-target gene

We have previously shown that the ETS1 gene is expressed in a tissue-specific manner, and encodes a transcription factor, that may be involved in lymphocyte development, activation and proliferation. To understand the ETS1 function in non-lymphoid cells, we have ectopically expressed ETS1 protein in a human colon cancer cell line, and studied its biochemical properties. The 51 kDa ETS1 protein expressed in transfected cells localized in both the nucleus and the cytoplasm, has similar biochemical properties compared to ETS1 protein expressed in lymphoid cells. The ectopically expressed ETS1 binds to the DNA in sequence-specific manner and the binding activity is affected by the flanking sequences outside the 'GGA' core. Our results also demonstrate that the DNA-binding activity of full-length ETS1 is similar in lymphoid and non-lymphoid cells. The ETS1 expressed in DLD-1 cells is biologically active since it induces a 54.5 kDa polypeptide, whose expression level correlates with the expression of ETS1 in DLD-1 cells.