Circadian clock genes Bmal1 and Period may regulate nocturnal spawning by controlling sex hormone secretion in razor clam Sinonovacula constricta

The circadian clock is an endogenous regulation mechanism that coordinates biological processes with daily changes, which are regulated by genes. Bmal1 and Period key genes their roles in reproductive development have been widely studied. spawning time of Sinonovacula constricta limited to the night even under external artificial stimulation, it might be internal clock. In this study, heart rate S. was higher between 20:00-04:00 at lower 12:00-16:00 during day, sex hormone contents were highest 00:00 lowest 18:00 ( P < 0.01). Therefore, these obvious changes rhythm indicate a nocturnal animal. open reading frame (ORF) comprises 1944 bp encoding 647 aa, while ORF 3111 1036 aa. both expressed four tissues, but they had opposite rhythmic expression patterns. 00:00-06:00 12:00-18:00, opposite, thereby suggesting involved positive negative pathways clock, respectively. Strong protein fluorescence signals proteins observed mature oocytes, spermatids, hepatocytes, epithelial cells siphons. After siRNA interference, significantly decreased 0.01), from 3 7 days treatment groups Therefore may regulate controlling secretion. These findings provide theoretical basis for understanding molecular related spawning, facilitate propagation mollusks.