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Circadian clock regulates developmental time through ecdysone and juvenile hormones in Bombyx mori

Jianfeng Qiu1,2, Taiming Dai1,2, Cheng Luo1,2

  • 1School of Biology and Basic Medical Sciences, Suzhou Medical College Soochow University, Suzhou, China.

Insect Molecular Biology
|February 23, 2023
PubMed

Insights

Disrupting the Cryptochrome 1 (Cry1) gene in Bombyx mori delays development by impairing ecdysone and enhancing juvenile hormone, revealing the circadian clock's role in hormonal balance for animal growth.

Area of Science:

  • * Molecular Endocrinology
  • * Chronobiology
  • * Developmental Biology

Background:

  • * The circadian clock is crucial for hormone regulation, but its precise role in coordinating hormonal homeostasis for animal development is not fully understood.
  • * Circadian rhythms influence physiological processes, including hormone biosynthesis and secretion, impacting overall organismal development.

Purpose of the Study:

  • * To investigate the impact of the core clock gene Cryptochrome 1 (Cry1) knockout on the developmental timing in Bombyx mori.
  • * To elucidate the molecular mechanisms by which the circadian clock regulates hormonal homeostasis, specifically focusing on ecdysone and juvenile hormone pathways.
  • * To understand how disruptions in circadian clock function affect key hormones regulating insect development.

Main Methods:

  • * Utilized a knockout model of the Cryptochrome 1 (Cry1) gene in Bombyx mori.
  • * Analyzed the ecdysone and juvenile hormone signaling pathways in fifth instar larvae.
  • * Quantified prothoracicotropic hormone synthesis, ecdysone production, and 20-hydroxyecdysone hemolymph titers.

Main Results:

  • * Cry1 knockout significantly delayed developmental time in Bombyx mori.
  • * Mutant larvae exhibited reduced prothoracicotropic hormone synthesis and insufficient ecdysone production, leading to delayed 20-hydroxyecdysone peaks.
  • * Enhanced juvenile hormone biosynthesis and signaling were observed in Cry1 mutants, contributing to prolonged developmental time.

Conclusions:

  • * The circadian clock, through genes like Cry1, is essential for maintaining hormonal homeostasis critical for normal animal development.
  • * Disruption of Cry1 impacts both ecdysone and juvenile hormone pathways, highlighting the intricate interplay between circadian rhythms and developmental hormones.
  • * This study provides key insights into the molecular basis of circadian clock-mediated regulation of animal development via hormonal balance.
Keywords:
Bombyx moriCry1circadian clockdevelopmental timehormone

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