Gene regulatory network

A genetically regulative network ( GRN) is a collection of DNA segments in a cell, which come into direct or indirect interaction with each other ( by their RNA and protein messengers), or with other substances in the cell, wherein the frequency at of the genes are transcribed in the network in mRNA control.

Usually produced each mRNA molecule, a specific protein (or a specific protein set). Firstly, the protein structural information contained and attach to the cell membrane or within the cell, to give it some structural properties. On the other hand, the protein can be an enzyme, such as a micro- machine, which acts as a catalyst for a particular reaction, such as the breakdown of nutrients or toxins. Other proteins, in turn, are used exclusively for the activation of other genes, and it is these transcription factors that play the main role in regulatory networks, or causal chains. By binding to the promoters regions in the beginning of other genes that they activate it and thus the production of other proteins and so on. Certain transcription factors are also used for ligation.

In unicellular organisms, the regulatory networks respond to the environment in order to maximize the chances of survival of the cell in this environment for a specified time. Such as a yeast cell, located in a sugar solution, enable genes to convert the sugar into ethanol. This process, which we bring to the production of wine in combination, the approach of the yeast cell to ensure their survival, to produce energy for propagation, which would improve their chances of survival under normal circumstances.

In multicellular animals, the same principle is used for the purpose of genetic effect chains that control the body shape. Every time a cell divides, this results in two cells, although they contain the same genome may differ in which genes are activated and produce proteins. Sometimes one makes " self-reinforcing cycle" that a cell maintains its genetic identity and passes. Far less understood, the mechanisms of epigenetics, wherein the modification of chromatin makes possible a cellular memory by preventing or enabling transcription. A common feature of multicellular animals is the use of morphogenic gradients, which in turn provide a system for the distribution of the position of a cell, so ensure that the cell knows where in the body it is located and can develop into a corresponding cell. A gene that was activated in a cell can leave this and diffuse into neighboring cells and activate genes entrance there, as far as they have already reached a certain stage in their development. These cells will then receive a new provision and can even turn produce other morphogens that transmit a feedback signal to the output cell. Over greater distances can morphogens use the active process of signal transduction. Such signals control at about the embryogenesis, the realization of " genetic blueprint" for building a complete organism from the beginning and sequenced over a series of time steps. They also control the cell regeneration of the adult body through the exchange of reciprocal feedback between the cells, the absence of this feedback may be due to mutations responsible for the formation of cell growths, known as cancer. In addition to the creation of new organic structures, the genetic effect chain also activates genes that produce structural proteins that give each cell the physical properties that it needs. It was previously thought, as biomolecular interaction pattern of an intrinsically predisposed subject probability that genetic networks are the result of cellular processes, and not its cause (see cellular Darwinism ). Anyway, recent experimental results suggest the hypothesis of cell determination close.