The gene regulatory network systems are basically made up of thousands of DNA sequences in a cell. There are also input signaling pathways and regulatory proteins known as transcription factors. The signaling pathways respond to signals from within the cells or from outside the cells and activate the transcription factor proteins.
The transcription factor proteins then bind with the DNA sequences and determine what genetic information is to be passed on to the mRNA (messenger RNA) molecules that are transcribed by the DNA. The mRNA processes the genetic information and synthesizes the required proteins.
Protein Synthesis
Here, it is important to understand that specific transcription factors interact with specific DNA sequences to pass on specific genetic information to the mRNA to synthesize specific proteins for specific purposes. These purposes range from simply responding to environmental stimuli to building up certain cell structures in certain locations and thereby, in sequential steps, the whole organism. It will also involve providing enzymes to catalyse reactions as well as giving rise to gene cascades that suppress or activate other cellular functions.
Cellular response to environmental stimuli is evident in both single-celled and multi-cellular organisms. In eukaryotes, which are large, multi-cellular organisms, proteins synthesized in one cell respond to signals from adjoining cells and infiltrate them. They then activate or inhibit the genes in these cells and bring about new protein synthesis. This process continues from cell to cell and is called a gene cascade.
The proteins synthesized in different cells may be different depending on which genes are turned on and which genes are suppressed. This is also seen in cell division, when resulting cells with the same genetic matter show different characteristics. This is what helps bring about genetic diversity.
Usually, the gene regulatory networks send distinct signals that tell cells that they must develop at certain locations and in a certain fashion. Such direction allows healthy development and growth to take place in an organism. Sometimes though some genes mutate and mess up the signals. So a cell may get the message to proliferate uncontrollably and this is what happens in the case of cancer.
