Distal promoter

Distal promoter elements are regulatory DNA sequences that can be many kilobases distant from the gene that they regulate.

They can either be enhancers (increasing expression) or silencers (decreasing expression). They act by binding activator or repressor proteins (transcription factors) and the intervening DNA bends such that the bound proteins contact the core promoter and RNA polymerase.

In T-cell development
T-cell development and activation is controlled by complementary placement of proximal and distal lck promoters. The generated environment of a Lck-PROX mice when approached with proximal promoter demonstrates maximal lck protein and normal thymic development, while distal promoters lead to deficient lck protein and unnormal thymic levels.

Further research at the late stage of thymocyte development reveals that distal Lck promoter with driven Cre will result in the distal lck gene promoter to drive Cre expression to be limited within innate-like T cells. There is a cell type specific function in innate-like T cells based on the distal lck promoter - driven Cre.