Turkish Journal of Biology




Several intracellular metabolic pathways in which multiple genes have a role affect the aging process. One important genetic factor associated with aging is klotho gene. In some recently published studies, klotho gene has also been associated with several types of cancer and identified as a tumor suppressor gene. Therefore, elucidation of the control of klotho gene expression has become more important. Results suggesting that the promoter region of human klotho gene could be epigenetically controlled by DNA methylation have been reported. In contrast, a study revealing whether a change in the expression level of DNMT enzymes in the cells affects klotho gene expression has not been found. Herein, the effects of DNMT3A and DNMT3B enzymes on the expression of klotho gene, an important genetic factor relating to the aging process and some human cancer types, were investigated. For this purpose, the expression levels of DNMT3A and DNMT3B in HEK293 cells were artificially changed, and the effect on klotho gene promoter activity was investigated using a reporter gene. The results of this research showed that DNMT enzymes have negative regulatory effects on klotho gene promoter organized as a chromatin structure, and they have an enhancing effect on promoter activity when it is located on plasmid DNA. These results elucidate the control mechanism of human klotho gene expression.


Aging, DNA methylation, DNMT-3A, DNMT-3B, klotho

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