Regulation of variable lifespan in castes of ants

描述（由申请人提供）：衰老是导致生理功能进行性下降的内在过程。为了应对环境的提示，在蚂蚁物种Harpegnathos saltator中，基因相同的个体可以切换到超过5倍的寿命，并在生殖和行为方面发生变化。蚂蚁中的工蚁向配子门的转变类似于体细胞重编程中的细胞去分化和再分化，这涉及基因表达和染色质结构的关键变化。脂肪体在配子体转变过程中的生理变化中起着至关重要的作用，包括卵巢激活，产卵和信息素（表皮碳氢化合物）分布的变化。因此，跟踪脂肪体中的基因表达谱将有助于阐明工人如何切换到gamergate并实现长寿。脂肪体转录组的初步数据显示了抗氧化剂、细胞增殖、信息素合成和胰岛素信号传导方面有趣的基因表达谱。这些数据与以前在其他物种中的研究一致，表明长寿的共同机制。首先分析果蝇成虫和幼虫的脂肪体转录组，并利用果蝇遗传学研究差异表达基因（DEG）的生物学功能。第二，这些DEG还含有转录因子（TF），其在从工蜂向配子体过渡期间脂肪体中基因表达谱的启动和维持中起重要作用。将选择在gamergate转换中具有强烈变化的TF，以使用果蝇遗传学和ChIP鉴定其靶基因。此外，我将寻找染色质修饰剂的靶基因。最后，我将讨论脂肪体如何调节卵巢激活。候选基因IGF-1是一种胰岛素样肽（insulin-like peptide，ilp），主要在人血吸虫中表达。跳跃式脂肪体。其功能可能类似于Dilp 6，其调节果蝇中的卵巢激活。为了研究IGF-1的功能，将进行脂肪体和卵巢的体外共培养。将使用细胞有丝分裂标记物磷酸化组蛋白H3（H3 S10 P）对这种作用进行化学检测。此外，将纯化的IGF- 1蛋白直接加入到工作者卵巢培养物中，然后进行H3 S10 P染色以测试卵巢活化。总之，这个项目将解决如何长寿是实现从非生殖工人生殖gamergates的过渡，以及在这个过渡中的脂肪体的作用。这项研究将为长寿的调控机制提供新的见解。

DESCRIPTION (provided by applicant): Aging is an intrinsic process leading to the progressive decline in physiological functions. In response to environmental cues, genetically identical individuals in the ant species Harpegnathos saltator can switch to more than 5 times longer lifespan, with changes in reproduction and behavior. The worker to gamergate transition in the ant is analogous to cell de-differentiation and re-differentiation in somatic cell reprogramming, which involves critical changes in gene expression and chromatin structure. The fat body plays crucial roles in the physiological changes during the gamergate transition, including ovary activation, egg production and variation in pheromone (cuticular hydrocarbon) profiles. Therefore, tracking gene expression profiles in the fat body will help clarify how a worker switches to a gamergate and achieves longevity. The preliminary data of the fat body transcriptome shows interesting gene expression profiles in antioxidants, cell proliferation, pheromone synthesis and insulin signaling. The data is consistent with previous studies in other species, suggesting a common mechanism underlying longevity. I will first analyze the adult and larvae fat body transcriptomes and use fly genetics to study the biological functions of the differentially expressed genes (DEGs). Second, these DEGs also contain transcription factors (TFs), which play an important role in the initiation and maintenance of gene expression profiles in the fat body during the worker to gamergate transition. TFs with strong changes in the gamergate transition will be selected to identify their target genes using fly genetics and ChIP. In addition, I will search for the target genes of chromatin modifiers. Last, I will address how th fat body regulates ovary activation. The candidate gene IGF-1 is an insulin-like peptide (ilp) predominately expressed in the H. saltator fat body. Its function may be similar to Dilp6, which regulates ovary activation in Drosophila. To address the function of IGF-1, in vitro co-culture of the fat body and ovary will be performed. This effect will be tested immunohistochemically, using the cell mitosis marker phosphor-histone H3 (H3S10P). In addition, purified IGF- 1 protein will be directly added to the worker ovary culture followed by H3S10P staining to test for ovary activation. In summary, this project will address how longevity is achieved in the transition from non- reproductive workers to reproductive gamergates, and the role of the fat body in this transition. This study will provide novel insights into the regulatory mechanisms underlying longevity.