Telomere And Telomerase Analysis

Telomere and telomerase:

A telomere is a repeating DNA sequence (for example, TTAGGG) at the end of the body's chromosomes. The telomere can reach a length of 15,000 base pairs. Telomeres function by preventing chromosomes from losing base pair sequences at their ends. They also stop chromosomes from fusing to each other. However, each time a cell divides, some of the telomere is lost (usually 25-200 base pairs per division). When the telomere becomes too short, the chromosome reaches a "critical length" and can no longer replicate. This means that a cell becomes "old" and dies by a process called apoptosis. Telomere activity is controlled by two mechanisms: erosion and addition. Erosion, as mentioned, occurs each time a cell divides. Addition

As a result, telomere length may not be a notably robust biomarker in this context. One of its weaknesses with its use, according to such a definition, is that telomere weakening is a feature of cellular senescence. Extrapolation of cellular telomere biology to the level of the tissue or organ, or the whole organism, is not straightforward. In order to do so, one must take into account the number of senescent cells (generated by both replicative senescence and stress or aberrant signalling-induced senescence), their location, and similarly the number and location of cells lost through insult, in each respective organ or tissue, to gauge properly the effect on its functional capacity. By using peripheral blood leukocyte telomere length as a surrogate for the functional capacity of solid tissues and organs is thus imprecise and prone to

Telomerase is an enzyme expressed during development that catalyses the addition of telomere repeats to chromosome ends. Post-neonatal human somatic cells repress telomerase expression. However, telomerase continues to be expressed in proliferative cells such as germ cells and stem cells. The high proliferation rate of neoplastic cells requires the maintenance of telomere length to assist immortalisation and carcinogenesis. Immortalisation is an important step toward malignant transformation of human cells and depends intensively on telomere maintenance (Queisser. 2013). Neoplastic cells acquire mutations that deregulate cell cycle control and increase cell proliferation. These cells require the maintenance of telomere length to facilitate their rapid division. In human cells there are two mechanisms in which telomeres are