Photoperiod is the main environmental driver of seasonal responses in organisms living at temperate and polar latitudes. Other external cues such as food and temperature, and internal cues including hormones, intervene to fine-tune phasing of physiological functions to the solar year. In mammals, the medio-basal hypothalamus (MBH) is the key integrator of these cues, which orchestrates a wide array of seasonal functions, including breeding. Here, using RNAseq and RT-qPCR, we demonstrate that molecular components of the photoperiodic response previously identified in ewes are broadly conserved in does (female goats, ), with a common core of ∼50 genes. This core group can be defined as the “MBH seasonal trancriptome”, which includes key players of the -tanycytes neuroendocrine retrograde pathway that governs intra-MBH photoperiodic switches of triiodothyronine (T3) production (, , and ), the two histone methyltransferases and and the secreted protein . Prior data in ewes revealed that T3 and estradiol (E2), both key hormones for the proper timing of seasonal breeding, differentially impact the MBH seasonal transcriptome, and identified cellular and molecular targets through which these hormones might act. In contrast, information regarding the potential impact of progesterone (P4) upon the MBH transcriptome was nonexistent. Here, we demonstrate that P4 has no discernible transcriptional impact in either does or ewes. Taken together, our data show that does and ewes possess a common core set of photoperiod-responsive genes in the MBH and conclusively demonstrate that P4 is not a key regulator of the MBH transcriptome.

中文翻译：

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光周期（而非黄体酮）对雌性山羊和母羊中基底下丘脑的转录组有强烈影响

光周期是生活在温带和极地纬度地区的生物体季节性反应的主要环境驱动因素。其他外部线索（例如食物和温度）以及内部线索（包括激素）会进行干预，以微调生理功能与太阳年的相位。在哺乳动物中，中基底下丘脑（MBH）是这些线索的关键整合者，它协调一系列广泛的季节性功能，包括繁殖。在这里，我们使用 RNAseq 和 RT-qPCR 证明，先前在母羊中发现的光周期响应的分子成分在母羊（雌性山羊）中广泛保守，具有约 50 个基因的共同核心。该核心组可被定义为“MBH 季节性转录组”，其中包括 -tanycytes 神经内分泌逆行途径的关键参与者，该途径控制 MBH 内三碘甲状腺原氨酸 (T3) 产生的光周期开关 (、、和)、两种组蛋白甲基转移酶和和分泌的蛋白质。先前对母羊的数据显示，T3 和雌二醇 (E2) 是季节性繁殖适当时机的关键激素，对 MBH 季节性转录组有不同的影响，并确定了这些激素可能发挥作用的细胞和分子靶标。相比之下，关于孕酮 (P4) 对 MBH 转录组的潜在影响的信息不存在。在这里，我们证明 P4 对母鹿或母羊没有明显的转录影响。总而言之，我们的数据表明母羊和母羊在 MBH 中拥有一组共同的光周期响应基因核心，并最终证明 P4 不是 MBH 转录组的关键调节因子。