Transient reduction of 5-methylcytosine and 5-hydroxymethylcytosine is associated with active DNA demethylation during regeneration of zebrafish fin

Abstract

Although dedifferentiation, transformation of differentiated cells into progenitor cells, is a critical step in the regeneration of amphibians and fish, the molecular mechanisms underlying this process, including epigenetic changes, remain unclear. Dot blot assays and immunohistochemical analyses revealed that, during regeneration of zebrafish fin, the levels of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) are transiently reduced in blastema cells and cells adjacent to the amputation plane at 30 h post-amputation (hpa), and the level of 5mC, but not 5hmC, is almost restored by 72 hpa. We observed that the dedifferentiated cells showed reduced levels of 5mC and 5hmC independent of cell proliferation by 24 hpa. Furthermore, expressions of the proposed demethylation- and DNA repair-related genes were detected during fin regeneration. Taken together, our findings illustrate that the transient reduction of 5mC and 5hmC in dedifferentiated cells is associated with active demethylation during regeneration of zebrafish fin.

Keywords: :

• zebrafish
• fin regeneration
• 5-methylcytosine
• 5-hydroxymethylcytosine
• active DNA demethylation

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

We thank Drs. Koichi Kawakami for providing the transgenic fish XIG8A; Hiroshi Ide and Toshiaki Nakano for NanoDrop 1000; Institute for Amphibian Biology for cryostat sectioning. We also thank the members of Kikuchi and Atsushi Suzuki laboratories in Hiroshima University for helpful discussion and critical comments. This study was supported by grants from Grant-in-Aid for Scientific Research from the MEXT (KAKENHI 23616002) to Y.K., and Hiroshima University Alumni Association Research Grant and Hiroshima University Support Foundation Research Grant to K.H.

Supplemental Materials

Supplemental materials may be found here: http://www.landesbioscience.com/journals/epigenetics/article/25653/