Sp1 and AP2 transcription factors are required for the human fragile mental retardation promoter activity in SK-N-SH neuronal cells.

The promoter of the human fragile mental retardation gene (FMR1) was functionally analyzed in order to identify elements responsible for its regulation. Plasmids carrying the wild type or different deleted-promoter sequences driving the chloramphenicol acetyl transferase gene (CAT) were transiently transfected into the SK-N-SH cells and the CAT activity was assessed. Deletion studies suggested that major regulatory elements are present in a DNA region between positions -123 and -51. Gel mobility shift and footprinting assays using a DNA fragment encompassing that promoter region showed that SP1 and AP2 transcription factors could be involved in the functioning of the FMR1 promoter.