1-1.6.1 Regulatory elements:

Gene expression is a complex multi-step process. Amongst various steps involved, transcription initiation is a vital key point in controlling gene expression.

Fundamental elements that regulate the process of transcription are:

• cis-acting elements comprising of special DNA sequences.
• trans-acting elements comprising of regulatory proteins.
• DNA –protein interaction.
• Protein-protein interaction
• RNA polymerase

•  cis-acting elements:

In Latin “cis”, means "same side as". Cis acting elements are thus a region of DNA or RNA that regulates the expression of genes located on the same molecule. The cis-regulatory elements are often binding sites for one or more trans-acting factors. Cis-element may be located upstream to the coding sequence of the gene it controls (in the promoter region or further upstream 5'), in an intron, or 3' to the gene's coding sequence, either in the untranslated or untranscribed region.

Fig1-1.6.1: Structure of eukaryotic gene with upstream regulatory elements