Topic of the Month
1 January 2014
Cell aging is a complex process in which numerous factors can be involved. Telomeres located at the ends of chromosomes play an important role here – they consist of repetitive DNA sequences and associated proteins (histones) that stabilize the DNA by forming a kind of protective cap. When DNA is copied during cell division, some of the DNA building blocks (nucleotides) at the ends of the chromosomes are not copied, with the result that the telomeres on the newly formed DNA strands get shorter with each cell division. With increasing telomere shortening the cell changes its pattern of gene activation, slows its rate of division, then halts division completely (senescence), and eventually dies (apoptosis). Telomerase, an enz- yme that forms telomeres, counteracts this cell aging process by adding nucleotides that would otherwise be lost to the ends of the new DNA strand. Cell aging and death are thus delayed. Both telomere length and the amount and activity of telomerase, along with other factors, determine how many times cells can divide. Studies have shown that these factors can be positively influenced by micronutrients.