Transcription and Gene Regulation

Transcription and Gene Regulation
     ⇒ Prokaryotic Genes
     ⇒ Transcription Initiation and Termination
     ⇒ The Lac Operon
     ⇒ Eukaryotic Gene Regulation
     ⇒ RNA Processing

The central dogma of molecular genetics proposes that the information in DNA is used to make RNA molecules through a process known as transcription and that the information in some RNAis used to make proteins by a process called translation. Transcription is carried out by RNA polymerases, whereas translation is catalyzed by enzymes associated with ribosomes. The RNAmolecules and proteins synthesized during the development and/or maintenance of an organism are responsible for an organism's characteristics.

The information for synthesizing a particular RNAis located in only one of the two DNA strands. The strand that contains the information for making an RNA molecule and that is "read" by an RNA polymerase is called the template strand or the sense strand. The strand that is complementary to the template is sometimes called the nonsense strand since it provides no information for the making of RNAor protein. Not all templates for coding RNAs occur on the same strand of DNA , however. Messenger RNAthat specifies the synthesis of a protein is called sense RNA, whereas RNA complementary to sense RNA is called antisense RNA.

Most genes, especially those encoding proteins, are regulated so they are expressed at the appropriate time and level needed to maintain the cell or to promote its growth and proliferation.

Gene expression includes both transcription and translation!