TSH-Dio2/Dio3-TH系统调控黑线仓鼠季节性繁殖的分子机制

Seasonal reproduction is a major cause leading to the population fluctuation in animals, photoperiod regulates the seasonal reproduction of the animal, and the hypothalamic - pituitary - thyroid axis (HPT) is an important path mediating photoperiodic regulation on the seasonal reproduction. There are some differences on the path and effects of HPT between animals with various genetic backgrounds. The striped hamster is a typically seasonal reproductive animal, and it is an ideal model to study the mechanisms of seasonal reproduction. The striped hamsters were respectively feed with different photoperiod conditions, the critical day length to active the reproduction activity and the length of time for activating the reproduction activity under different photoperiod conditions were detected; Sequencing of transcriptome, analysis of GO function and KEGG Pathway, phage display technology and yeast one-hybrid means were used to detect the concrete pathway of TSH-Dio2/Dio3-TH system mediated by photoperiod to regulate seasonal reproduction; the differential expression of the factors in the TSH-Dio2 / Dio3-TH system under different photoperiod conditions and various seasons were examined by RNA hybridization in situ, immunohistochemistry and quantitative real-time PCR technology, and the effect of each factor on the concentration of FSH / LH in blood and the number of follicles were also analyzed. This study　will provide scientific basis for reveal the mechanisms of the seasonal reproduction and population fluctuation for the rodent populations, also provide new ideas and methods for making comprehensive measures to control the rodents.

季节性繁殖是动物种群数量波动的主要原因，光周期调控季节性繁殖，下丘脑-垂体-甲状腺轴(HPT) 是光周期调控季节性繁殖的重要通路。动物间遗传背景不同，光周期作用于HPT的路径及效应也存在差异。黑线仓鼠是典型的季节性繁殖动物，是研究季节性繁殖机制的理想模型。本研究用不同光周期处理黑线仓鼠，检测光周期激活其繁殖活动的临界日长及不同光周期激活繁殖活动所需时长；通过转录组测序、GO功能和KEGG Pathway分析、噬菌体展示技术、酵母单杂交等，检测光周期介导TSH-Dio2/Dio3-TH系统调控繁殖活动的作用路径；采用RNA原位杂交、免疫组化、实时定量PCR检测TSH-Dio2/Dio3-TH系统中各因子在不同光周期及季节的差异表达，并分析各因子对血液FSH/LH的浓度及卵泡数量的效应。为揭示动物季节性繁殖及其害鼠种群数量波动机制提供科学依据，并为农业害鼠综合治理措施的制定提供新思路和方法。

季节性繁殖现象是影响动物种群数量波动的关键因素，研究动物季节性繁殖机制有利于合理控制动物种群数量，维护生态系统的平衡。光周期是调控动物季节性繁殖活动的重要环境因子，TSH-Dio2/Dio3-TH系统是介导光周期调控动物繁殖活动的主要作用通路之一。黑线仓鼠作为华北地区的主要农田害鼠之一，具有典型的季节性繁殖特征。本项目研究了光周期调控黑线仓鼠脑组织差异表达的基因，并分析了主要作用通路，其中催产素信号通路、cAMP信号通路及钙信号通路在光周期调控黑线仓鼠繁殖活动中发挥重要作用；研究了光周期调控黑线仓鼠的性腺发育，卵泡刺激素(FSH)、黄体生成素(LH)等生殖激素的合成及分泌的生物学效应，长光周期促进黑线仓鼠性腺发育、FSH和LH的合成及分泌；研究了光周期调控黑线仓鼠繁殖活动路径中TSHB/TSHR、OPN5等基因在下丘脑、卵巢和睾丸等组织的差异表达，及其调控黑线仓鼠的繁殖活动的效应，其效应在组织、性别间存在差异；探究了TSH-Dio2/Dio3-TH系统启动子通过甲基化调控黑线仓鼠季节性繁殖活动的机制及效应，甲基化抑制基因的表达，在不同光周期条件及季节间甲基化水平存在差异；ERB调控黑线仓鼠发情周期不同阶段攻击行为的强度。该研究为揭示动物季节性繁殖机制提供理论依据，为农业害鼠综合治理措施的制定提供新思路和方法。