Life events, including maternal care, stress adaptability, and early hardship, may leave genetic imprints throughout the earliest phases of development. This may affect whether and how our genes release the data that will support the development of our future resilience, abilities, and capacity for health.
The chemistry of our genes and environment impacts our health and well-being, and this is what epigenetics are all about. A rapidly expanding field of study transforms our knowledge of how nature influences nurture.
Adenine, guanine, cytosine, and thymine are the four bases that makeup DNA; each base may have a distinct methylation pattern. These methylation patterns are established throughout the development of the human genome and may have little impact on an individual’s epigenome.
Then, genes are switched on or off based on these methylation patterns. The term for this is epigenetic regulation.
Because they aid in imprinting specific genes on our chromosomes — the process by which we get genetic information from our parents — the methylation patterns of genes play a crucial role throughout development.
Long non-coding RNAs, DNA methylation, and histone modification are all combined to accomplish this. Repressing the expression of intergenic regions and possibly damaging elements inside these intergenic regions is another vital function of DNA methylation.
Other methylation functions include:
- The inactivation of the X chromosome.
- The regulation of tissue-specific gene expression.
- The silencing of retroviral sequences.
- Genomic imprinting.
Additionally, it may be a significant factor in conditions like cancer.
Histone modifications are a class of posttranslational alterations that affect the stability of the genome, gene transcription, and chromatin architecture. Acetylation, methylation, phosphorylation, and ubiquitination are among the most frequent changes.
These PTMs are added to or subtracted from the amino acid residues of histone proteins and other biological components by various histone-modifying enzymes. These reversible modifications have an impact on the chromatin structure and gene activation.
For instance, depending on the amino acid residues acetylated and the level of acetylation present, histone acetylation may either enhance or reduce DNA accessibility for transcriptional machinery and cause gene activation or repression.
Histone methylation modifies gene expression by adding or removing a methyl group from lysine or arginine residues. It has been related to the activation or repression of several biological processes, including cell development, stress response, and aging. It can activate or repress genes.
An essential epigenetic process that influences gene expression is RNA modification. However, how these changes impact other epigenetic systems and how they control the genetic code is unclear.
More than 130 distinct RNA modifications have been found and mapped to the single nucleotide level. These maps are handy, but our knowledge of how they work biologically lags.
The adenosine m6A modification, located in the 5' untranslated region, is one of the most prevalent RNA modifications (UTR). It is crucial for ribosome and translation structure.
The translation of m6A modification into a functional signaling event requires specific “reader” proteins, such as DNA and histone methylation. Eukaryotic initiation factor 3 and the YT521-B homology domain-containing protein family (YTHDF1 and YTHDF2) are examples of known m6A readers (eIF3).
Turning genes on or off are known as gene expression (the genes that make proteins). Cells are created in this manner.
This is accomplished in prokaryotic organisms using transcription and RNA polymerase. It is far more complex in eukaryotic cells, however.
Transcription and the production of mRNA are regulated at many points. Different sets of proteins must be attached to cis-regulatory DNA regions to regulate each step.
Frequently, these regulatory proteins are also in charge of the epigenetic markers’ DNA methylation and histone modification.
In addition, a variety of long non-coding RNAs may alter the expression of genes, which in turn affects how active they are. For instance, DNA methylation, long non-coding RNAs termed Xist and TSix, and histone modification all regulate X-chromosome inactivation. These RNAs are inheritable and may be transferred from one generation to the next.