Specialized structures called telomeres are found at the ends of linear chromosomes and are essential for maintaining genetic and chromosomal stability. Their main job is to protect the genetic material from enzymatic degradation and prevent it from being lost during cellular processes.
Main roles of telomeres:
Protection against degradation
Telomeres act as protective caps that keep the ends of chromosomes safe from enzymatic breakdown and degradation. Maintenance of the integrity of the genetic material in the chromosomes depends on this protection.
Fusion or breakage prevention
Telomeres are essential to prevent chromosomal ends from fusing or breaking with neighboring chromosomes. This ensures that the chromosomes do not undergo unplanned structural changes and continue to exist as separate units.
Cell Division and Telomere Shortening
Telomeres shorten with each round of cell division. Repeated DNA sequences form telomeres, and the number of repeats decreases with each cell cycle. The cell eventually loses its ability to divide when its telomeres become too short. This system helps prevent the formation of damaged cells.
Cell Senescence
Cell senescence is a process of gradual shortening of telomeres during each cell division. Cells that reach permanent growth and stop dividing are said to be in a state called senescence. This system acts as a defense against the growth of harmful or mutated cells.
Function of telomerase
By introducing repetitive DNA sequences to telomeres, the enzyme telomerase can prevent telomere shortening. However, proteins strictly regulate the activity of telomerase. Telomerase activity is often low in somatic cells, causing telomere length to progressively decrease with each cell division.
Preserving Genome Integrity
Telomere play an important role in maintaining the integrity of the genome. They prevent dangerous chromosomal end events including homologous recombination (HR) and homologous end joining (NHEJ) from occurring. Genomic instability and anomalies during mitotic cell division may result from these events.
In summary, telomere are critical components that support the general stability and well-being of the genome. Chromosome ends are protected, fusion or breakage is prevented, cell division is regulated by telomere shortening, and genetic integrity is maintained throughout cellular processes.
