冷觉通过激活胰岛素生成细胞调节果蝇体型大小

发布时间：2018-03-19 19:41

本文选题：Bergmanns’rule　切入点：果蝇　出处：《浙江大学》2016年博士论文　论文类型：学位论文

【摘要】：环境因素对个体发育的影响是一个经久不衰的研究命题,在众多因素中,气候的变更,温度的变化无处不在,它对动物个体发育乃至种群进化产生巨大的影响。19世纪,德国生物学家Carl Bergmann发现,动物个体的体型与生存地区纬度呈正相关关系,纬度越高,温度越寒冷的地区,动物个体体型越大,纬度越低,温度越温暖的地区,动物个体体型越小。这就是著名的Bergmann's rule,它总结了生存温度对温血动物体型影响的一般规律。在非脊椎动物中,动物体形与温度呈负相关的关系更加普遍存在,我们称之为温度体形规律(Temperature-Size Rule,TSR)。从19世纪初开始,人们对各种动物进行研究和考察,尝试解释温度影响动物体型的原因,至今我们对其分子细胞机制仍然知之甚少。模式动物果蝇是用来研究温度影响体型规律的良好载体,早在1940年,人们已经开始利用果蝇研究温度影响体型的规律,果蝇在其适宜的生存温度范围内,成熟体的体型大小具有强烈的温度可塑性,比如低温环境(18℃)下饲养的果蝇的体型比在高温环境(25℃)下饲养的果蝇大10%左右。果蝇幼虫阶段是发育积累并决定成熟体体型大小的决定性阶段,于是我们主要研究幼虫的发育机制。果蝇幼虫与成虫一样,具有丰富的感知系统,包括化学感知、机械感知、温度感知等。在幼虫外周分布着丰富的初级感知神经元,它们投射到脑中央神经元形成简单且功能齐全的神经网络。初级感知神经元是动物感知外界环境因素(温度)的必经之路,我们以研究果蝇幼虫的温度感知神经系统为立足点,以人工操控神经元的兴奋性为手段,结合基本的细胞分子检测方法研究温度影响个体发育的机制。果蝇胰岛素是调节幼虫发育的关键分子之一并且具有物种保守性,主要的几个果蝇胰岛素由胰岛素生成细胞IPCs (insulin producing cells),一个分泌性神经元,合成与分泌。我们发现阻断IPCs可以消除低温促进幼虫体型增大的影响,而激活IPCs则可以促进幼虫体型增加,通过在体钙成像实验,我们发现低温刺激可以兴奋IPCs,通过荧光定量PCR,免疫组织化学和免疫印记实验,我们发现低温可以促进其中的果蝇胰岛素RNA的合成和胰岛素的分泌。说明IPCs做为一个发育调控关键细胞和一个低温兴奋性神经元在低温促进幼虫发育过程中的重要性。更进一步,我们通过筛选得到一个标记果蝇头部神经元的11216-Gal4品系,在体钙成像实验的数据表明,低温刺激可以激活11216-Gal4标记的神经元,通过鉴定和比对,我们确认这些神经元为幼虫的初级冷觉感知神经元。我们利用GRASP (GFP reconstitution across synaptic partners)技术,证明这些11216-Gal4标记的初级冷觉感知神经元的轴突与IPCs的树突形成物理上的突触联系；利用光遗传结合钙成像的方法,我们发现激活11216-Gal4标记的初级冷觉感知神经元可以激活IPCs,说明这两群神经元形成功能性的神经环路。同时我们发现,激活11216-Gal4标记的初级冷觉感知神经元可以促进IPCs中的果蝇胰岛素RNA的合成和胰岛素的分泌,并且导致果蝇的体型增大,很好的再现了低温刺激的效果。我们的研究揭示了冷觉信号刺激胰岛素合成分泌并促进个体生长的神经信号传递通路,为TSR提供了一个神经环路水平的机制性解释,也为Bergmann's rule的解释提供了借鉴。
[Abstract]:The environmental factor is a research topic of enduring influence on individual development, among other factors, climate change, temperature change is everywhere, it has great influence on the.19 century animal ontogeny and population evolution, the German biologist Carl Bergmann discovered that size and survival latitude is positively related to the individual animal the temperature is, the higher the latitude, the cold area, the individual animal bigger in lower latitude area, temperature is warm, the smaller animal individual. This is the famous Bergmann's rule, its general rule summarizes the influence of temperature on the survival of warm blooded animal size. In vertebrates, the animal body with temperature. The negative correlation is more prevalent, we call the body temperature regulation (Temperature-Size Rule, TSR). From the beginning of nineteenth Century, people study and investigation of all kinds of animal, try Explain the temperature influence reasons of animal body, so far we on the molecular and cellular mechanisms are still poorly understood. Animal model of Drosophila is a good carrier to study the influence of temperature size rule, in early 1940, people have begun to use the influence of temperature on size of fruit flies, flies its survival in the suitable temperature range, the size of mature body the temperature has a strong plasticity, such as low temperature (18 DEG C) were smaller than Drosophila under high temperature (25 DEG C) about feeding 10%. Fruit fly Drosophila larvae stage of development is accumulated and decisive stage of mature body size, so we mainly study the developmental mechanism of larvae of Drosophila larvae. And as adults, with rich perception system, including chemical sensing, mechanical sensing, temperature sensing. In the primary distribution of peripheral larvae to perceive God rich by yuan, their investment Shot to the brain central neurons form neural network is simple and functional. The primary sensory neurons is animal perception of external environmental factors (temperature) of the temperature sensing we the only way which must be passed, nervous system of Drosophila larvae as the starting point, the excitability of neurons in the artificial control means, combined with the basic research of cellular and molecular mechanism of temperature effect detection method the ontogeny of Drosophila. Insulin is one of the key molecules regulating larval development and species conservation, several major Drosophila insulin producing cells by insulin IPCs (insulin producing cells), a secretory neuron, synthesis and secretion. We found that blocking the IPCs can eliminate the effect of low temperature effects of larval size increased, while the activation of IPCs can be to promote the increase in the size of larvae, the imaging experiment of body calcium, we found that low temperature stimulation can be excited by IPCs. Light quantitative PCR, immunohistochemistry and Western blotting experiments, we found that low temperature can promote the synthesis and secretion of insulin in the Drosophila insulin RNA. IPCs as a key developmental control cell and a low temperature low temperature promote excitatory neurons in the larval developmental importance process. Further, we obtained through screening the 11216-Gal4 strain of a Drosophila head marker of neurons, that in body calcium imaging experiment data, low temperature stimulation can activate 11216-Gal4 labeled neurons, through the identification and comparison, we confirmed that these neurons of primary sensory neurons of larvae. We use GRASP (GFP reconstitution across synaptic partners) technology, that axons and the primary IPCs cryesthesia sensory neurons of these 11216-Gal4 markers for dendritic synapses physically; using light calcium combined with genetic The imaging method, we found that the initial activation of 11216-Gal4 labeled neurons cold perception can activate IPCs, indicating that the two groups of neurons form functional neural circuits. At the same time, we found that the primary sensory neurons labeled by 11216-Gal4 activation of IPCs can promote the synthesis and secretion of insulin in the fruit fly RNA insulin, and increase the size of Drosophila melanogaster well, the reproduction of the low temperature stimulation effect. Our study reveals the cold stimulation of insulin synthesis and secretion and promote individual growth of neural signal pathway, provides a mechanism of a neural circuit level explanation for TSR, but also provide a reference for the interpretation of rule Bergmann's.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q43

【相似文献】