The effects of Mkrn3 on delayed puberty

项目总结 青春期是身体发展第二性征并成为 能够繁殖的。青春期的开始是由于包括遗传影响在内的复杂因素的相互作用。 青春期疾病的基因突变，包括中枢性早熟(CPP)和青春期延迟， 为了解青春期和生殖的神经内分泌机制提供了窗口。 性早熟最常见的遗传原因是Makorin环功能缺失突变 Finger Protein 3(MKRN3)，约占家族CPP的40%。MKRN3的功能和调节是 不是很清楚，但它的蛋白质结构暗示了E3泛素连接酶和RNA结合活性。表达式 MKRN3在小鼠下丘脑中含量很高，并在青春期开始之前迅速下降。这支持了它作为 第一个被发现的青春期启动抑制剂，假设作用于GnRH和/或其激活剂的上游，如 Kispeptin。 目前的提案旨在探索MKRN3表达的变化是否同样会导致青春期延迟 开始使用创新的小鼠模型和人类研究。初步研究表明， 脑室注射重组病毒的野生型雌性小鼠的青春期表型 过表达MKRN3。该模型将用于探索MKRN3的S作用机制，包括其 在生殖过程中对已知的神经内分泌参与者的影响。这种重组病毒将被用来评估MKRN3 在双侧立体定向手术后，过度表达也会导致青春期后性腺激素减退 注射到下丘脑的弓状核。在一个更具体的过度表达模型中，MKRN3将是 利用一种新的转基因小鼠模型更好地识别Kispeptin神经元中选择性过表达 MKRN3的S瞄准了。此外，鉴于初步研究中观察到MKRN3表达增加 可以推迟青春期的开始，将对青春期延迟的儿童进行筛查以进行编码 和MKRN3中的非编码变体，因为这在以前没有被探索过。 青春期延迟会使儿童面临长期健康风险。因此，阐明影响和 MKRN3延缓青春期开始的作用机制对促进儿童健康具有重要意义。 包括改善青春期疾病的诊断和管理，并可作为未来的治疗方法 目标。使用提出的工具来确定MKRN3的S的行动目标对于理解这位关键球员至关重要 对青春期和生殖的神经内分泌控制。

PROJECT SUMMARY Puberty is a remarkable time during which the body develops secondary sexual characteristics and becomes capable of reproduction. Puberty onset is due to a complex interplay of factors, including genetic influences. Genetic mutations in disorders of puberty, including central precocious puberty (CPP) and delayed puberty, provide windows into understanding the neuroendocrine mechanisms of puberty and reproduction. The most common genetic cause of precocious puberty is due to loss-of-function mutations in Makorin Ring Finger Protein 3 (MKRN3), and accounts for ~40% of familial CPP. The function and regulation of MKRN3 are not well understood, but its protein structure suggests E3 ubiquitin ligase and RNA binding activities. Expression of Mkrn3 is high in the mouse hypothalamus and rapidly declines before puberty onset. This supports its role as the first identified inhibitor of puberty onset, hypothesized to act upstream of GnRH and/or its activators, such as kisspeptin. The current proposal aims to explore if alterations in Mkrn3 expression can similarly lead to delayed pubertal onset using innovative mouse models and human investigation. Preliminary studies demonstrate a delayed puberty phenotype in wild type female mice injected intracerebroventricularly with a recombinant virus overexpressing Mkrn3. This current model will be used to explore MKRN3’s mechanism of action, including its impact on known neuroendocrine players in reproduction. This recombinant virus will be used to assess if Mkrn3 overexpression can also lead to hypogonadotropic hypogonadism postpubertally following bilateral stereotaxic injection into the arcuate nuclei of the hypothalamus. In a more specific model of overexpression, Mkrn3 will be selectively overexpressed in kisspeptin neurons using a novel transgenic mouse model to better identify MKRN3’s targets. Additionally, given the observation in preliminary studies that increases in Mkrn3 expression can delay puberty onset, a well-characterized cohort of children with delayed puberty will be screened for coding and non-coding variants in MKRN3 as this has not been previously explored. Delayed puberty puts children at risk for long-term health risks. Therefore, elucidating the impact and mechanisms of action of MKRN3 in delaying pubertal onset has important implications for advancing child health, including improving diagnosis and management of pubertal disorders and can serve as a future therapeutic target. Using the proposed tools to identify MKRN3’s targets of action is critical to understanding this key player in the neuroendocrine control of puberty and reproduction.