Use in clinical context
DNA has sections that code for proteins, but DNA is contained within the nucleus and proteins are made at the ribosomes. To get the relevant sections of code to the ribosomes DNA is transcribed into mRNA, which is transported out of the nucleus to the ribosomes. Transcription is regulated by transcription factors which interact with promotors to initiate transcription. Once initiated, RNA polymerase moves along the gene adding a nucleotide at a time to the strand of RNA.
The process of transcription is tightly regulated, but there are many steps involved where errors can be made, particularly with regulation. This means that proteins may be produced when they shouldn’t be or not made when they should be with important implications for cellular function.