PDF(Pubmed)
Abstract：
Delayed fatherhood results in a higher risk of inheriting a new germline mutation that might result in a congenital disorder in the offspring. In particular, some FGFR3 mutations increase in frequency with age, but there are still a large number of uncharacterized FGFR3 mutations that could be expanding in the male germline with potentially early- or late-onset effects in the offspring. Here, we used digital polymerase chain reaction to assess the frequency and spatial distribution of 10 different FGFR3 missense substitutions in the sexually mature male germline. Our functional assessment of the receptor signaling of the variants with biophysical methods showed that 9 of these variants resulted in a higher activation of the receptor´s downstream signaling, resulting in 2 different expansion behaviors. Variants that form larger subclonal expansions in a dissected postmortem testis also showed a positive correlation of the substitution frequency with the sperm donor\'s age, and a high and ligand-independent FGFR3 activation. In contrast, variants that measured high FGFR3 signaling and elevated substitution frequencies independent of the donor\'s age did not result in measurable subclonal expansions in the testis. This suggests that promiscuous signal activation might also result in an accumulation of mutations before the sexual maturation of the male gonad with clones staying relatively constant in size throughout time. Collectively, these results provide novel insights into our understanding of the mutagenesis of driver mutations and their resulting mosaicism in the male germline with important consequences for the transmission and recurrence of associated disorders.
摘要：
父亲的延迟导致遗传新的种系突变的风险更高，这可能导致后代的先天性疾病。特别是,一些FGFR3突变的频率随着年龄的增长而增加，但仍有大量未表征的FGFR3突变可能在雄性种系中扩展,在后代中可能有早期或晚期效应.这里,我们使用数字聚合酶链反应评估了性成熟男性种系中10种不同FGFR3错义替换的频率和空间分布.我们用生物物理方法对变体的受体信号的功能评估表明，这些变体中的9个导致受体下游信号的更高激活，导致2种不同的扩张行为。在解剖的死后睾丸中形成较大亚克隆扩张的变体也显示出与精子供体年龄的替代频率正相关，和高度和不依赖配体的FGFR3活化。相比之下,检测到高FGFR3信号传导和取代频率升高而不依赖于供体年龄的变异体未导致睾丸中可测量的亚克隆扩增.这表明，混杂信号激活也可能导致雄性性腺性成熟之前突变的积累，克隆在整个时间内保持相对恒定的大小。总的来说，这些结果为我们理解驱动突变的诱变及其在男性种系中的镶嵌性提供了新的见解,对相关疾病的传播和复发有重要影响.
