IGEM:Melbourne/2008/Concepts/Diagram legend

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Physical Components

Promoter

A Promoter

• DNA sequence that act as an upstream initiator for transcription of a gene
• If a promoter is active, the downstream genes will be transcribed from DNA to RNA and the RNA can then be translated into proteins
• If a promoter is repressed, the downstream genes are not transcribed therefore no protein is produced
• Promoters are generally labelled with a P followed by a subscript that provides information about the promoter. For example, the P_trc-2 promoter in the toggle switch is a fusion of promoters from the tryptophane (the tr part) and lac (the c part) genes
• For more info, see the Wikipedia entry

Gene

A Gene

• DNA sequence that codes for a particular protein
• Is transcribed into RNA which is translated into a protein
• For our purposes, a gene is essentially a blueprint for a component of our system and through the promoter, we can choose when the component is produced
• Again, see the Wikipedia Entry for more detailed information if you want

Protein

A Protein

• A string of amino acids whose sequence is determined by the gene code they were assembled from
• Form complex 3D shapes that affect the function of the protein
• While genes are confined to the nucleus of a cell, proteins can generally diffuse around and even out of the cell
• As always, the Wikipedia Entry has far more information than I can give here

Actions

Positive action

• Indicates that the action is a positive one
• Eg. This arrow from a gene to a protein shows that the gene produces the protein
• Eg. This arrow from a protein to a promoter shows that the protein interacts with the promoter to activate it, causing the genes downstream of the promoter to be expressed

Negative action

• Indicates that the action is a negative one ie. the first component is inhibiting the second component from acting somehow
• Eg. This arrow from a protein to a promoter means that the protein interacts with the promoter to prevent downstream genes from being expressed
• Eg. This arrow from a temperature to a protein means that at that temperature, the protein will not function