| Summary: | <p>Abstract</p> <p>Background</p> <p>The understanding of cutaneous pigmentation biology is relevant from the biologic and clinical point of view. The binding of α-melanocortin and its specific receptor, on the plasma membrane of melanin synthesising cells, plays a crucial role in melanins biosynthesis. Furthermore, loss of <it>MC1R </it>function is associated with an increased incidence of melanoma and non-melanoma skin cancer. The expression of the α-melanocortin receptor gene is highly controlled but, at the present, region responsible for tissue-specific activity of the gene promoter has not been identified.</p> <p>Methods</p> <p>We have cloned the genomic sequences upstream the human MC1R coding gene. A DNA fragment of 5 kilobases upstream the human MC1R encoding sequence was placed in front of a reporter gene and several deletion mutants of such fragment have been prepared. These constructs have been tested for the ability to drive the melanocyte-specific gene expression of the reporter gene using transfection experiments in melanocyte and non-melanocyte cell lines. From these experiments we identified a DNA fragment with the ability to drive the gene transcription in a tissue-specific way and we used this small DNA fragment in DNA-protein interaction assays.</p> <p>Results</p> <p>We show that the 150 base pairs upstream the MC1R gene initiation codon are able to drive the melanocyte-specific gene transcription. Furthermore, we provide experimental evidences suggesting that on such minimal melanocyte-specific gene promoter can assemble tissue-specific complexes.</p> <p>Conclusion</p> <p>The present results strongly imply that the transcriptional regulation of the melanocyte-specific MC1R gene requires an internal promoter located in the 150 base pairs upstream the initiation codon.</p>
|
|---|
