Diurnal rhythm of the ridge formation in regenerating scale and its regulation by clock genes and melatonin

在硬组织中，以一天为单位形成的增量线的存在比以前更为人所知。日增量线的形成机制尚未明确，因此，本研究采用金鱼再生鳞片进行实验，阐明其形成机制。在自发鳞片再生过程中成骨细胞特异性基因的表达中，它与哺乳动物膜内骨再生具有相似的基因表达。再生尺度显示，每天在外层形成脊状（增量线）。在再生尺度时钟基因的表达中，per-3基因的表达具有明显的昼夜节律。提高对再生尺度脊线形成的认识，有助于阐明硬组织日增量线形成的机制。

In the hard tissue the presence of the incremental line formed as a unit about a day has been known than before. The formation mechanism of the diurnal incremental line has not been clarified, then, in this study, the experiment was conducted to clarify the mechanism using a regenerating scale of the goldfish. In the expression of osteoblast-specific genes during spontaneous scale regeneration, it shared similarities in gene expression with mammalian intramembranous bone regeneration. The regenerating scales showed that the ridges(incremental lines) are formed in the outer one on each day. In the expression of clock genes in regenerating scale, a clear circadian rhythm was observed in the expression of per-3 gene. Improved understanding of the ridge formation in regenerating scale will help elucidate the mechanism of formation of the diurnal incremental line in the hard tissue.