Decrease in cytosine methylation at CpG island shores and increase in DNA fragmentation during zebrafish aging

作者：Shimoda Nobuyoshi^*; Izawa Toshiaki; Yoshizawa Akio; Yokoi Hayoto; Kikuchi Yutaka; Hashimoto Naohiro

来源：Age, 2014, 36(1): 103-115.

DOI：10.1007/s11357-013-9548-5

• Aging
• Zebrafish
• DNA methylation
• CpG island shore

Age-related changes in DNA methylation have been demonstrated in mammals, but it remains unclear as to the generality of this phenomenon in vertebrates, which is a criterion for the fundamental cause of senescence. Here we showed that the zebrafish genome gradually and clearly lost methylcytosine in somatic cells, but not in male germ cells during aging, and that age-dependent hypomethylation preferentially occurred at a particular domain called the CpG island shore, which is associated with vertebrates%26apos; genes and has been shown to be hypomethylated in humans with age. We also found that two CpG island shores hypomethylated in zebrafish oocytes were de novo methylated in fertilized eggs, which suggests that the zebrafish epigenome is reset upon fertilization, enabling new generations to restart with a heavily methylated genome. Furthermore, we observed an increase in cleavage of the zebrafish genome to an oligonucleosome length in somatic cells from the age of 12 months, which is suggestive of an elevated rate of apoptosis in the senescent stage.

• 出版日期2014-2