Complex transcriptional regulation of the BCL2L12 gene: Novel, active promoter in K562 cells.

The BCL2L12, one of the latest discovered members of the BCL2 family, has both pro- and anti-apoptotic roles that are cell-type-dependent. Its role in tumorigenesis is highly implicated. Sixty-three splice variants of this gene have been identified so far, with significant differences in expression patterns between various cancer cell lines. Presently, little is known regarding the regulation of expression of the BCL2L12 gene. For the vast majority of BCL2L12 gene splice variants, the 5'- and 3'-untranslated regions as well as their transcriptional regulation have not been determined yet. The aim of this study was to get insight into the regulation of the BCL2L12 gene transcription in human chronic myelogenous leukemia (K562) cell line. Our results point to the activity of novel transcription start site of the BCL2L12 gene and indicate that Sp1 and GATA-1 transcription factors could be involved in the regulation of BCL2L12 gene expression in K562 cells. The previously reported active promoter of BCL2L12 gene differs from the one we described in our study. If this novel BCL2L12 promoter is confirmed to be active in other malignancies, transcripts generated from this region could be considered as new cancer-specific biomarkers. The results of our study contribute to the better understanding of the transcriptional regulation of the BCL2L12 gene.