Nucleic Acids

Introduction
The previous exercise dealt with differentiation, and specifically with the events leading to differential gene activity. In olecular terms, this process involves regulation using DNA as a primer molecule for the selective synthesis of RNA. DNA-primed RNA synthesis is termed “transcription.”

Transcription is a complex series of reactions which involve the use of an RNA polymerase enzyme, known as transcriptase. If the reaction occurs in reverse, that is, with an RNA primer synthesizing DNA, the process is known as reverse transcription, and the enzyme is reverse transcriptase. This latter process is important for RNA virus replication in general, and is most significant when examining oncornagenic virus. Oncornagenic viruses are RNA-containing viruses that are also causal agents for some forms of cancer (primarily in birds). Reverse transcription is also important in the development of amphibians, and in the process of gene amplification.