Psychiatric and micro RNA disease
Until recently, it was thought that only 2% of human DNA-producing proteins were important. The rest has been called piracetol “undesirable”. It is believed that unwanted DNA accumulates through random processes without physiological consequences. After the genome project did not find enough “mutations” to explain more diseases or to explain the evolutionary change, 98% of the remaining DNA acquired a new meaning. Ten years after the genome project, ENCODE (research involving more than 100 institutions around the world for the encyclopedia of DNA elements) found that a large percentage of 98% of DNA was significant and functioned as large and small RNAs. have vital physiological functions. The normative debate on DNA now places vital DNA between 20% and 40%. Even in the smallest figure, the regulatory DNA is ten times larger than the “genes.” It is also now clear that 50% of total DNA consists of skipping genes that are critically important in evolution (see the article on jumping genes).
It has now been discovered that thousands of small RNAs are vital in all aspects of physiology and genetic regulation. Many large RNAs have dramatic overall effects on the structure and function of complete chromatin. Recently, it has been discovered that in psychiatric diseases, many have altered microRNAs in the brain and in the blood. In this post we will discuss the current findings about psychiatric diseases and microRNAs. Experiments with animals may show altered behavior with specific microRNAs. These could one day be part of the diagnosis and treatment of brain diseases and psychiatric illnesses.
A previous article described the difficulties in characterizing the genetics of psychiatric illness despite strong correlations. Few specific mutations have correlated exactly with the mechanisms of psychiatric illness. Many environmental factors seem to play a role in psychiatric illness, including physical and mental stress at the beginning of life. Epigenetic mechanisms can also be important, such as DNA labels and histones, protein and RNA alterations. Recently it was discovered that small RNAs are an important means to modify gene expression in many regions, including the brain.
Each microRNA can modify hundreds of different genes (the microRNA is usually called miRNA, and I use a microRNA to facilitate reading). Studies show that they are involved in the regulation of half of all genes. The microRNAs are approximately 22 nucleotides in length. They are part of a complex to silence messenger RNAs that are about to produce proteins. MicroRNA can affect codes in several ways. They can silence a particular chain of messenger RNA. They can interrupt the process. They can block genes. They may slightly alter the results, as often happens in adult neurons. They modify neural networks by adjusting the expression of genes in a particular way.
Most research has focused on fetal microRNAs, neuroplasticity and brain diseases. But, they can also affect behavior and mood. The current theories of psychiatric illness focus on the alteration of gene expression that modifies brain structures and their activity. Studies include animals and humans, as well as cell studies. Due to the great complexity involved, multiple approaches are often used at the same time.
Making a microRNA is surprisingly complex. The large enzymes of RNA polymerase II and III transcribe the DNA microRNAs. First, they make “primary transcripts” of specific genes or other genes where parts of DNA (introns) are edited. Either a pri (primary) form such as micro-RNA or individual clusters.
In the early stages of this process, the RNA creates a spectacular hairpin curve. Then, the editing is done by complex enzymes (ribonucleases) that cut them even more, breaking the hairpin curve. Another molecule serves as a rule to determine the precise locations of the cuts. Then it is cut to a smaller size of 70 to 110 nucleotides, where it is called “micro RNA precursor”. This is sent from the nucleus to the cytoplasm where it is cut again by a different enzyme (called DICER) that produces a double micro RNA of approximately 22 nucleotides in length.