Characterization of a silencer that modulates transcription of the human distal aldolase A promoter.

Transcription from the distal promoter (pL) of the human aldolase A gene is driven by both positive and negative cis-acting elements. With footprinting and gel mobility assays we defined: (i) the position of the negative regulatory cis-element (AldA-NRE), which spans a GA-rich sequence; (ii) the sequence of AldA-NRE, which is critical for protein specific binding and is homologous to other silencer-like motifs. Removal of the negative cis-element fully restores the expression of the distal promoter. Insertion of the AldA-NRE upstream from a heterologous promoter results in a 6-fold decrease in CAT reporter gene expression, suggesting that AldA-NRE might be involved in a more general type of mechanism that mediates repression of gene transcription.