Simply stated, transcription is the process by which the genetic code is transferred from DNA to RNA.  The DNA sequence is copied through an enzymatic process, using RNA polymerase, to produce a complementary RNA strand.  Transcription is the beginning process that leads to the translation of the genetic code into proteins or a functional peptide.  This two-step process is responsible for gene expression, or the process in which a gene’s DNA sequence is converted into structures and function of a cell.

 

Transcription takes place in the nucleus of the cell, mainly in active transcription sites, sometimes called “transcription factories.”  Here transcription is initiated by a particular DNA gene sequence that is recognized by RNA polymerase.  At this point, the enzyme stretches open the double helix and begins synthesis of the RNA strand.  Transcription is terminated by either terminator sequences located within the RNA strand that signal the RNA polymerase to stop or by using a special protein that causes the enzyme to dissociate from the DNA strand.

 

Recently, Roger D. Kornberg won the 2006 Nobel Prize in Chemistry for work done on eukaryotic transcription.  He has devoted much time to determining the structure of the RNA polymerase using, x-ray crystallography, and to working out the necessary protein components for the transcription process.