introduction

Epigenetics is the study of the changes that occur on top of the dna with without changing the genome sequence, but still affect the expression of our genes and thebohy shape our phenotype. This is the Reason Why even Identical Twins, who have almost the same genome sequence, are different from Each other: Due to their distinct epigenome.

Epigenetic traits, unlike the genome, are configured all along development. They are flexible and reversible. This is the Reason Why We We have so many distinct cells in our body, each with its own shape, size and molecular charactteristics that determin their function. And that is why scientist can reverse almost any somatic cell into a pluripotent cell (Cells that Are Able to Differiary, or Mature, Into the Three Primary Groups of Cells That Form A Human, Eectoderm, Endoderm and Mesoderm); Important for Cell Therapy.

Nevertheless, The Epigenome is therefore heritable Across Generations. It is influenced by the Dietary Habits and Life Styles of our Parents. However, they can be reversed by our own habits and pass the changes to our Children.

Epigenetic changes

The most important epigenetic changes in an organism include DNA methylation and histone modifications. In order to get a clearer idea of ​​it, we want to discuss it in detail.

DNA methylation

DNA methylation is essentially the attachment of a methyl group to certain areas of the DNA sequence. If the DNA methylation occurs near the sequence of a gene, the expression of this gene is suppressed drastically. DNA methylation is essential for normal development. It is usually deleted during the formation of the cygote, but is restored in the embryo at the time of implantation. Most DNA methylation play an important role in the genomic character and inactivation of the X chromosome, and when they are dysregulated, they contribute to serious illnesses such as cancer.

Histon modification

Histon modifications include a number of chemical changes that take place on the so-called histone proteins. These proteins serve as roles for the long DNA that is packed in our cells. The more a gene range is packed, the more difficult it is to express it and define a phenotype. The best known histone modifications include histoneacetylation and methylation. These modifications not only change the chromatin structure, but also determine the recruitment of other proteins at the DNA to activate or deactivate certain genes and even repair damaged areas of the genome. Thus, histone modifications for the correct expression of genes and the avoidance of cells with abnormal genominformation are important. They are associated with a number of diseases and their condition can be used to monitor the effectiveness of medical treatment.

What about the molecular level?

The expression of a gene can be regulated into proteins during its transcription into RNA or during its translation. A gene that is prevented from the formation of proteins cannot perform its function in a cell or not express its phenotypical characteristic in an organism. This has an impact on a variety of crucial biological processes, including the normal development or the progress of diseases.

Epigenetics comprises at least 3 different mechanisms that regulate the expression of genes. Epigenetics exercises regulation via covalent modifications (DNA methylation and histone modifications), transcription factors and micrornas.

Covalent modifications

As explained above, covalent modifications include the DNA methylation and hydroxymethylation of cytosine residues in certain regions of the genome, the so-called CPG points. They also include histone modifications such as lysine and arginine methylation and acetylation as well as serine and threonin phosphorylation and lysine-subiquitination and sumoylation. Coovalent modifications exercise control over the genome by:

1. Rebuild the chromatin structure, which makes genes either made less or more accessible to expression and/or through
2. Recruiting or preventing the binding of proteins required for the expression of the genome.

The mechanism of the histone modifications is more unclear than that of DNA methylation. While DNA methylation often acts as a suppressive or silent factor in gene expression, the histone modifications are likely to work in different ways. An acetylated histone at a point of the genome can have opposite effects than an acetylated histone in another place in the genome. Likewise, methylation on a histone lysine can have a different effect than the methylation of another lysine on the same histone. Covalent modifications are installed by proteins, the so -called writer, and removed from proteins, the Erasern. Medicines that inhibit writers or eraser proteins are used today to treat certain types of cancer. Other histone changes associated with other diseases and types of cancer still have to be discovered.

Transcription factors (TF)

Transcription factors (TF) are another mechanism of epigenetic regulation. They can act as positive or negative regulators of the expression of genes. Transcription factors bind to DNA sequences that are located in certain regions of the genome. These sequences can be either amplifier of the transcription or insulators that have a negative or positive effect on the transcription. Enhancers serve as nodes for transcription factors that promote the expression of a gene. Insulators can either abolish the suppressive effect of DNA methylation or the promoting effects of enhancers.

Mircornas (Mirnas)

Micrornas (Mirnas) are RNA molecules with 17-25 nucleotids that do not encode for any protein and are therefore never translated. However, they have an oppressive effect on the expression of a series of genes. It was calculated that each Mirna can regulate the translation of around 100 to 200 messenger-RNAs (mrnas: RNAS that encodes proteins). Micrornas work by pairing with mrnas, which in most cases leads to reducing the mRNA or in some other cases to reduce its translation into proteins.

conclusion

At Moleqlar Analytics there are experts who deal with the piling of proteins and histone modifications. Together with the pharmaceutical industry, clinics and other partners, we want to decrypt the unknown relationships between these molecular structures in humans.