DNA Transcription
DNA Transcription
National Human Genome Research InstituteDNA transcription is a process that involves the transcribing of genetic information from DNAto RNA. The transcribed DNA message is used to produce proteins. DNA is housed within the nucleus of our cells. It controls cellular activity by coding for the production of enzymes and proteins. The information in DNA is not directly converted into proteins, but must first be copied into RNA. This ensures that the information contained within the DNA does not become tainted.
There are three main steps to the process of DNA transcription.
DNA Transcription
DNA consists of four nucleotide bases [adenine (A), guanine (G), cytosine (C) and thymine (T)] that are paired together (A-T and C-G) to give DNA its double helical shape.There are three main steps to the process of DNA transcription.
- RNA Polymerase Binds to DNA
DNA is transcribed by an enzyme called RNA polymerase. Specific nucleotide sequences tell RNA polymerase where to begin and where to end. RNA polymerase attaches to the DNA at a specific area called the promoter region.
- Elongation
Certain proteins called transcription factors unwind the DNA strand and allow RNA polymerase to transcribe only a single strand of DNA into a single stranded RNA polymer called messenger RNA (mRNA). The strand that serves as the template is called the antisense strand. The strand that is not transcribed is called the sense strand.
Like DNA, RNA is composed of nucleotide bases. RNA however, contains the nucleotides adenine, guanine, cytosine and uricil (U). When RNA polymerase transcribes the DNA, guanine pairs with cytosine and adenine pairs with uricil.
- Termination
RNA polymerase moves along the DNA until it reaches a terminator sequence. At that point, RNA polymerase releases the mRNA polymer and detaches from the DNA.
