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Gene regulatory pathway. In genetics, a regulator gene, regulator, or regulatory gene is a gene involved in controlling the expression of one or more other genes. Regulatory sequences, which encode regulatory genes, are often at the five prime end (5') to the start site of transcription of the gene they regulate. In addition, these sequences ...
A regulatory sequence is a segment of a nucleic acid molecule which is capable of increasing or decreasing the expression of specific genes within an organism. Regulation of gene expression is an essential feature of all living organisms and viruses.
Regulation of gene expression, or gene regulation, [1] includes a wide range of mechanisms that are used by cells to increase or decrease the production of specific gene products (protein or RNA). Sophisticated programs of gene expression are widely observed in biology, for example to trigger developmental pathways, respond to environmental ...
Changes in the regulation of gene networks are a common mechanism for prokaryotic evolution.An example of the effects of different regulatory environments for homologous proteins is the DNA-binding protein OmpR, which is involved in response to osmotic stress in E. coli but is involved in response to acidic environments in the close relative Salmonella Typhimurium.
Structure of a gene regulatory network Control process of a gene regulatory network. A gene (or genetic) regulatory network (GRN) is a collection of molecular regulators that interact with each other and with other substances in the cell to govern the gene expression levels of mRNA and proteins which, in turn, determine the function of the cell.
Given the short sequences of most promoter elements, promoters can rapidly evolve from random sequences. For instance, in E. coli, ~60% of random sequences can evolve expression levels comparable to the wild-type lac promoter with only one mutation, and that ~10% of random sequences can serve as active promoters even without evolution. [5]
Genetic regulatory circuits also have an ability to be evolutionarily rewired without the loss of the original transcriptional output level. [8] [9] This rewiring is defined by the change in regulatory-target gene interactions, while there is still conservation of regulatory factors and target genes. [8] [10]
Mutations can involve the duplication of large sections of DNA, usually through genetic recombination. [10] These duplications are a major source of raw material for evolving new genes, with tens to hundreds of genes duplicated in animal genomes every million years. [11]