Promoter activity

Promoter activity is a term that encompasses several meanings around the process of gene expression from regulatory sequences —promoters and enhancers. Gene expression has been commonly characterized as a measure of how much, how fast, when and where this process happens. Promoters and enhancers are required for controlling where and when a specific genes is transcribed. Promoter activity is a term that encompasses several meanings around the process of gene expression from regulatory sequences —promoters and enhancers. Gene expression has been commonly characterized as a measure of how much, how fast, when and where this process happens. Promoters and enhancers are required for controlling where and when a specific genes is transcribed. Traditionally the measure of gene products (i.e. mRNA, proteins, etc.) has been the major approach of measure promoter activity. However, this method confront with two issues: the stochastic nature of the gene expression and the lack of mechanistic interpretation of the thermodynamical process involve in the promoter activation. The actual developments in metabolomics product of developments of next-generation sequencing technologies and molecular structural analysis have enabled the development of more accurate models of the process of promoter activation (e.g. the sigma structure of the polymerase holoenzyme domains) and a better understanding of the complexities of the regulatory factors involved. The process of binding is central in determining the 'strength' of promoters, that is the relative estimation of how 'well' a promoter perform the expression of a gene under specific circumstances. Brewster et al., using a simple thermodynamical model based on the postulate that transcriptional activity is proportional to the probability of finding the RNA polymerase bound at the promoter, obtained predictions of the scaling of the RNA polymerase binding energy. This models support the relationship between the probability of binding and the output of gene expression The problem of gene regulation could be represented mathematically as the probability of n molecules — RNAP, activators, repressors and inducers — are bound to a target regions. To compute the probability of bound, it is needed to sum the Boltzmann weights over all possible states of P {displaystyle P} polymerase molecules on DNA. Here in this deduction P {displaystyle P} is the effective number of RNAP molecules available for binding to the promoter. This approach is based in statistical thermodynamics of two possible microscopic outcomes: The statistical weigh of promoter unoccupied Z(P) is defined: