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Daily rhythms in male mice meiosis
S Rienstein1, A Dotan, L Avivi
1Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Israel.
Abstract:
Various processes associated with mammalian reproduction exhibit circadian rhythms, yet no information is available concerning the presence of rhythmicity in meiosis-the crucial process of the production of sex cells. Following meiosis in cells derived from male mice exposed in vivo to daily light-dark cycles (LD), we were able to demonstrate the existence of a clear 24h rhythmic pattern in the overall meiotic process, as well as in the production of spermatids, the immediate products of male meiosis and the precursors of male sex cells. On the other hand, cells of free-running male mice exposed to constant external conditions (light-light, LL) revealed a 12h rhythmic pattern in the overall meiotic process, indicating the endogenous nature of this rhythm. The existence of a 24h rhythm component in a long-lasting (approximately 12 days) process like meiosis suggests a time-dependent gating mechanism that controls the dynamics of miocyte arrest and release. The 12h rhythms observed in LL may indicate the presence of either a 12h rhythm component or of two 24h endogenous components, phased 12h from each other, that are coupled in daily LD cycles and split up in the free-running condition (LL). The rhythmic pattern observed in the course of male meiosis might have significant implications for male reproduction.
Insights
Male meiosis, the process of sex cell production, exhibits a 24-hour rhythm under light-dark cycles. This circadian rhythm in meiosis suggests implications for male reproductive timing and function.
Area of Science:
- Reproductive Biology
- Chronobiology
- Cell Biology
Background:
- Circadian rhythms influence various mammalian reproductive processes.
- Rhythmicity in meiosis, essential for sex cell production, remained uninvestigated.
Purpose of the Study:
- To investigate the presence and nature of circadian rhythms in male meiosis.
- To explore the implications of meiotic rhythmicity for male reproduction.
Main Methods:
- Analysis of meiotic progression and spermatid production in male mice under controlled light-dark (LD) cycles.
- Observation of meiotic patterns in male mice under constant light (LL) conditions to assess endogenous rhythms.
Main Results:
- A distinct 24-hour rhythmic pattern was observed in overall male meiosis and spermatid production under LD conditions.
- Male mice in constant light (LL) exhibited a 12-hour rhythmic pattern in meiosis, indicating an endogenous rhythm.
- The 24-hour rhythm suggests a time-dependent gating mechanism controlling meiotic progression.
Conclusions:
- Male meiosis displays endogenous circadian rhythmicity.
- This rhythmicity in meiosis may play a significant role in regulating male reproductive processes.