摘要

Objectives: Genes within a DNA sequence are expressed throughout life, via the DNA expression into RNA which through the messenger RNA is translated from nucleic acid coding into proteins which are the brains of the cells. Some genes are always on, controlling the ability of the DNA to replicate and repair itself. Others are regulatory that can be turned on or off. Introduction: The rate of expression of a particular gene is controlled by its location within nucleosomes and by the activity of the cell’s transcriptional machinery. Transcription of a gene requires the unwinding of a nucleosome, which makes the gene accessible to a basal transcription complex. Cell differences are determined by the expression of different sets of genes. Gene expression becomes more variable with advancing age. Aging differs phenotypically among individuals and within tissues from the same individuals. Materials / method: Gene expression is regulated by genetic effects and environmental factors. For example, childhood trauma has been found to be associated with increased inflammatory gene expression in late life, affecting both health and the aging process. Results: A significant proportion of age-related changes in gene expression appear to be tissue-specific with only a few general age effect in expression across tissues. The 43 shared genes in skin and adipose tissue have shown a single common identifiable pathway related to the stress response. Signalling pathways are the key biological mechanisms that transduce extracellular signals to affect transcription factor-mediated gene regulation within cells. A key role cell signalling plays in biological systems is to relay extracellular signals to regulate intracellular gene expression. Conclusion: The response of biological systems to changing environmental conditions and aging factors is a dynamic process. Activation of different signalling pathways can lead to numerous physiological or cellular responses, such as cell proliferation, death, differentiation, and metabolism. Any interruption that occurs within these extra−/intra-cellular communication chains can cause aging and diseases.