5hydroksimetyylisytosiini

5-hydroxymethylcytosine, often abbreviated as 5hmC, is a modified base of cytosine, a fundamental component of DNA. It is formed by the enzymatic oxidation of 5-methylcytosine (5mC), another epigenetic modification. This conversion is primarily carried out by the ten-eleven translocation (TET) family of enzymes. 5hmC is considered a stable epigenetic mark and is present in various organisms, including mammals, and plays a role in gene regulation.

The presence of 5hmC in the genome is not random; it is often found in actively transcribed gene bodies and regulatory regions. This localization suggests its involvement in modulating gene expression, although the precise mechanisms are still under investigation. 5hmC can influence chromatin structure and protein binding, thereby affecting the accessibility of DNA to transcription factors and other regulatory proteins. It is also thought to be an intermediate in DNA demethylation pathways, where it can be further processed by other enzymes like thymine DNA glycosylase (TDG).

Studies have linked aberrant levels or distribution of 5hmC to various biological processes and diseases, including development, cancer, and neurological disorders. The ability to detect and quantify 5hmC has opened new avenues for understanding epigenetic regulation and its implications in health and disease. Research continues to explore the full spectrum of 5hmC's biological functions and its potential as a biomarker.