Transcription represents the first step in gene expression. It is therefore not surprising that transcription is a highly regulated process and its control is essential to understand the flow and processing of information required by the cell to maintain its homeostasis. During transcription, a DNA molecule is copied into RNA molecules that are then used to translate the genetic information into proteins; this logical pattern has been conserved throughout all three kingdoms of life, from Archaea to Eukarya, making it an essential and fundamental cellular
process. Even though some viruses that encode their genome in an RNA molecule use it as a template to make mRNA, others
synthesize an intermediate DNA molecule from the RNA, a
process known as reverse transcription, from which regular
transcription of viral genes can then proceed in the host cells
