The information to produce a protein is coded in the cells in deoxyribonucleic acid (DNA). Transcription is the process in which a DNA sequence is copied into a ribonucleic acid (RNA) sequence. This RNA sequence is a messenger RNA (mRNA) because it will be then translated into a functional protein. For this, the DNA sequence is read and an RNA strand is synthesized by an RNA polymerase (an enzyme that synthesizes RNA molecules from a DNA template). During the process participate other proteins, such as DNA binding proteins, activators, coactivators, etc. (accessory proteins).
