title: An essential cis-acting element of the lck-3' promoter regulates the expression of p56(lck) in metastatic colorectal-cancer cells.
abstract: Detection of lck-specific transcripts has been discussed as a marker for metastasis of epithelial tumor cells. Since it is known that lck expression is regulated post-transcriptionally, it was fundamental to us to identify lck in human colorectal cancer cell lines also at the protein level. Subsequently, RT-PCR was used to confirm that lck-producing colorectal cancer cell lines contain mature transcripts initiated exclusively from the 3' promoter element. When transcriptional activity of the two different lck promoter elements was characterized in the colon cancer cell lines, we found the 3' promoter preferentially activated. Based on the results obtained from truncating this promoter element at its 5' end, we were able to define the major transcriptional activity of the downstream promoter to be regulated within a small region of only 90 bp upstream from the start site for lck type I transcripts. This finding will contribute to the identification of lymphocyte-specific transcription factors involved in the activation of the lck gene in metastatic colorectal carcinoma cells.
authors.affiliation: UNIV ERLANGEN NURNBERG,INST HUMANGENET,SCHWABACHANLAGE 10,W-8520 ERLANGEN,GERMANY.
authors.forename: K
authors.initials: K
authors.lastname: Mayer
authors.forename: W
authors.initials: W
authors.lastname: Ballhausen