Genes and gene expression.

Gene therapy is the process whereby a therapeutic protein is synthesized from a DNA molecule (gene) that has been inserted into the cells. The goal is to produce the desired protein in the proper quantity in the proper location. Successful designing of vectors for gene therapy requires knowledge of gene structure and regulation. The gene is comprised of protein-coding sequences (called exons) that are interrupted by noncoding sequences (called introns). The expression of a gene in a tissue is regulated by proteins that bind to specific deoxyribonucleic acid sequences generally upstream from the first exon, in the deoxyribonucleic acid promoter domain. Understanding the mechanisms of gene regulation provides the deoxyribonucleic acid sequences necessary to direct expression of specific genes in the right tissue at the proper time in the desired amount.