FIGURE 1.

Reversible biochemical modifications affect the transfer of genetic information (the Central Dogma). As per the central dogma, the genetic information passes from DNA, through RNA, to protein. However, epigenetic DNA base modifications [e.g., 5-methylcytosine (5-mC), 5-hydroxymethylcytosine (5-hmC), N⁶-methyladenine (6-mA), and N⁶-hydroxymethyladenine (6-hmA)] and histone protein modifications [e.g., methylation (me) and acetylation (ac) of amino acids] affects RNA metabolism (including splicing, export, stability, and translation efficiency) and play crucial roles in the regulation of cellular growth, development, and protection from environmental stress. Similarly, the dynamic RNA modifications [e.g., N⁶-methyladenosine (m⁶A), N¹-methyladenosine (m¹A), and N⁶-hydroxymethyladenosine (hm⁶A)] encrypt an additional layer of information and dynamically regulate the biological processes. Small-interfering RNA (siRNA) plays important role in recruitment of DNA methyltranferase for DNA base modification, methylated mRNA bases (e.g., m⁶A) play role in protein synthesis, the histone 3 (H₃) protein trimethylated (me³) at 4th lysine of (H₃K₄me³) affects the transcription process.