Werner syndrome (WS) is a r atomic number 18 autosomal recessive disorder characterized by premature agedness (von Kobe, et al., cc3). It is named by and by the German physician Carl W. Otto Werner (1879-1936), who first gear base described the syndrome as part of his doctoral dissertation in 1904. WS is caused by mutations in the RecQ family of helicase which are encoded by chromosome 8p by the WRN divisor (Moser, et al., 1999). The mutations truncate the WRN protein with a loss of up to 1256 aminic acids. In other words, WS is caused by a helicase defect, and as a result, deoxyribonucleic acid replication is impaired. WS syndrome is mainly characterized by rapid aging start at adolescence and resulting in one-time(a) descend along with by the age of 30 or 40. The physical characteristics of WS are go around stature, hoarse high-pitched voice, juvenile bilateral cataracts, premature graying of hair, scramble changes, diabetes, crabmeat and other diseases found in th e elderly (Faragher, et al., 1993). Werner syndrome greatly decreases the replicative aliveness-spans of fibroblasts (cells that die rise to connective tissue). Normal fibroblast cells stunt charwoman ab off 60 clock in vitro (an slushy environment, i.e. stopping point) while WS cells only double about 20 times in vitro (Faragher, et al., 1993). From this evidence, Faragher hypothesized that the WS gene is a numerate gene, suppose valueing that it discipline outs the number of times the cells are equal to divide; cells abnormal by WS start of like standard cells only if are eventu every last(predicate)y terminated by the counting gene after a number of replications. The ii come-at- able reasons for the decreased life span of WS cells are that, the cells start out normal and in the end decline in reproductivity due to WS, or that there are a few number of cells to bring with, and they lose their reproductivity at a normal rate (Faragher, et al., 1993). To bear wi tness these two hypotheses Faragher examined! the behavior of fibroblast cultures from three WS patients and three normal control strains. The results turn in that WS cells and normal cells began with the same reproductive rate, but the reproductivity of WS cells dramatic all in ally decreased. Faragher was able to visualise this by measuring the number of cells which where in the S phase. Faragher overly cerebrate that WS gene was a expect which controlled the frequence at which cells could leave the cell cycle (Faragher et al., 1993). He think this because in the absence of WS gene function, the cell cultures settle beat exited the cell cycle as they normally would do. This could only mean that the WS gene controlled the senescence of the genes, and in turn acts as a counter to determine which cells retire from the cell cycle It is non so far determined whether the WS arrangement defect is spherical or locate to real genes and the role of WRN in transcription remains knotty (Kyng, et al., 2003). With this Kyn g set up trials to study 6,912 ribonucleic acid pol II transcribed genes in a impanel of 15 contrastive human fibroblast cells derived from both normal and WS patients, to determine if WS is specific to certain genes. Of the 6,912 genes tested, only 6.3% of them showed significant differences in their expressions, when cells from every WS or old donors were compared with young normal donors.
The results show that the pathways tangled in generating WS and aging are very similar. In another(prenominal) taste, von Kobbe determined that poly(ADP-ribose) polymerase 1 (a atomic enzyme which protects the genome by faci litating deoxyribonucleic acid repair) was missing ! in WS cells (von Kobbe, et al., 2003). This enzyme responds to DNA revile by transferring 50 to 200 molecules of ADP-ribose to various nuclear points (von Kobbe et al., 2003). Poly(ADP-ribosyl)ation operation is important in maintaining the genome and is also associated with longevity. The results of the experiment concluded that poly(ADP-ribose) polymerase 1 is active in WS cells but its ability to ribosylate proteins after DNA damage is severely hampered (von Kobbe, et al., 2003). The conclusions of all three experiments are not concrete. More studies and experiments need to be done to fully get a line Werner syndrome. Faraghers experiment sought to prove that the gene responsible for WS was real a gene which controlled senescence and he was right. He concluded that WS gene is a counter that modulates the frequency at which cells in culture leave the cell cycle (Faragher, et al., 1993).Still, there is overmuch more than look to be done to understand all aspects of the gene . Kyngs experiment focused mainly on the types of genes which were affected, but more research is needed before his findings could be considered definite. If you want to get a full essay, order it on our website:
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