社会性昆虫品级分化的基因调控

品级分化是社会性昆虫的主要特征之一,包括雌性分化为生殖个体和非生殖个体,这一分化过程是受基因调控的。目前对社会性昆虫品级分化相关基因表达研究的报道较多,但是对这一分化的调控机制并不十分清楚,对这些基因的来源还存在争议。文章对社会性昆虫品级分化相关基因的研究概况作一综述,以期对以后相关方面的深入研究有所帮助。     

社会性昆虫级型和行为分化机制研究进展

社会性的出现是生物演化过程中的重要革新, 理解社会性的演化和调控机制具有重要的理论和实际意义。社会性昆虫的个体间有着明显的级型分化和劳动分工, 这有利于它们适应复杂的环境变化。理解社会性昆虫如何产生不同的形态、行为和生活史特性, 一直是进化和发育生物学的重要目标。随着测序技术的不断更新及生物信息学的快速发展, 已经有众多关于社会性昆虫级型和行为分化机制的研究报道。本文通过整理社会性昆虫研究的已有成果, 从环境因素、生理调控和分子机制等方面对社会性昆虫级型和行为分化机制相关研究进展进行了综述, 并对未来的研究方向做出了展望。根据现有证据, 社会性昆虫所生活的生物环境(食物营养、信息素、表皮碳氢化合物)和非生物环境(温度、气候等)均能直接或间接影响社会性昆虫级型和行为的分化; 保幼激素、蜕皮激素、类胰岛素及生物胺等内分泌激素和神经激素对社会性昆虫的级型和行为分化也有重要的调控作用; 此外, 遗传因素、新基因等DNA序列或基因组结构上的变化以及表观遗传修饰、基因的差异表达等基因调控机制均能不同程度地影响社会性昆虫的行为分化。本文建议加强昆虫纲其他社会性类群如半翅目蚜虫和缨翅目蓟马等的社会性行为及其演化机制的研究, 以加深对社会性昆虫起源及其行为演化的理解和认识。     

蜜蜂级型分化机理

蜜蜂Apis spp.能有效地为多种植物及农作物授粉, 具有重要的经济和生态价值; 蜜蜂作为高度真社会性昆虫, 已成为社会生物学研究的模式生物。社会性昆虫的生殖劳动分工具有重要的进化意义, 而级型分化是形成生殖劳动分工的基础。近年来, 关于蜜蜂级型分化的研究已取得诸多重要成果, 其机理也得到了较为深入的阐释。营养差异引发蜜蜂幼虫的级型分化。蜂王浆中的主要蛋白组分之一--Royalactin是诱导蜂王发育的关键营养因子, 而脂肪体细胞的表皮生长因子受体介导了Royalactin的这种蜂王诱导作用。DNA甲基化是重要的表观遗传机制之一, 且与个体发育和疾病发生紧密相关, 近来的研究表明DNA甲基化在蜜蜂级型分化过程中发挥重要的调控作用。此外, 越来越多的研究进一步深化了人们对内分泌系统调节级型分化作用的认识。本文从关键营养因子调控、 表观遗传调控和内分泌调节3方面综述蜜蜂级型分化的机理, 并对未来的研究提出可能的方向。     

表观遗传学: 生物细胞非编码RNA调控的研究进展

表观遗传学是研究基因表达发生了可遗传的改变, 而DNA序列不发生改变的一门生物学分支, 对细胞的生长分化及肿瘤的发生发展至关重要。表观遗传学的主要机制包括DNA甲基化、组蛋白修饰及新近发现的非编码RNA。非编码RNA 是指不能翻译为蛋白的功能性RNA分子, 其中常见的具调控作用的非编码RNA包括小干涉RNA、miRNA、piRNA 以及长链非编码RNA。近年来大量研究表明非编码RNA在表观遗传学的调控中扮演了越来越重要的角色。文章综述了近年来生物细胞非编码RNA调控的表观遗传学研究进展, 以有助于理解哺乳动物细胞中非编码RNA及其调控机制和功能。     

蜜蜂非编码RNA研究进展

非编码RNA(Non-coding RNA,ncRNA)是指不编码蛋白质的功能性RNA的统称,主要包括微小RNA(MicroRNA,miRNA)、长链非编码RNA(Long non-coding RNA,lncRNA)和环状RNA(Circular RNA,circRNA)等,它们在各种生命活动中发挥着重要的调控作用.蜜蜂不仅是重要经济授粉昆虫,还是人类研究动物复杂社会行为的最佳模式生物.近年来,蜜蜂ncRNA亦是该领域研究热点,成果不断涌现,本文在介绍ncRNA的特征、分类及其主要作用机制的基础上,主要针对ncRNA在蜜蜂劳动分工、级型分化、繁殖性能和免疫防御等方面调控作用的最新研究进展进行综述,以期为深入探究ncRNA提供借鉴和参考.     

长链非编码RNA对骨质疏松症调控作用的研究进展

骨质疏松症是以骨密度减低和骨微结构破坏为特征的骨代谢性疾病,可引起骨脆性增加和骨折风险增大。近年来,随着骨质疏松症病因研究的深入,基因领域的机制研究获得了更多发现。长链非编码RNA参与多种生理和病理变化,已成为控制基因表达和影响多种生物过程的重要表观遗传调节因子。大量研究表明,长链非编码RNA能够通过调控干细胞分化和骨重塑等过程对骨质疏松症产生影响。该文主要针对长链非编码RNA对干细胞、成骨细胞及破骨细胞增殖、分化调控作用进行综述,旨在探讨长链非编码RNA在骨质疏松症形成机制中的调控作用,为骨质疏松症的预防和临床治疗提供理论依据。     

社会性昆虫的组织及通讯行为

社会性昆虫在自然界有很重要的生物学意义,社会性昆虫具有3个主要特征,真社会性昆虫包括全部蚂蚁、白蚁及部分胡蜂、蜜蜂。它们具有明显的等级分化和个体分工。通过报警、集聚、化学招引、摇摆舞等方式,社会性昆虫在其内部做了很好的通讯交流从而使其社会组织得到了很好的发展。     

昆虫microRNA的研究进展

MicroRNA (miRNA)是20世纪90年代发现的一类由内源基因编码的长度约21~24 nt的非编码单链RNA分子, 广泛存在于真核生物中, 对基因的转录后调控起着非常重要的作用。本文简要介绍了miRNA的产生与调控机制, 同时从昆虫miRNA的发现鉴定、 靶基因预测与功能验证, 昆虫miRNA的序列特征与进化, 果蝇和非果蝇类昆虫miRNA生物学功能以及供昆虫miRNA研究的网络平台等方面对昆虫miRNA的最新进展进行了综述, 旨在为进一步研究昆虫miRNA提供借鉴和参考。对昆虫miRNA的研究表明其参与调控细胞分化、 增殖及凋亡、 胚胎发育、 器官发生、 形态构建、 生理代谢、 环境协调、 行为认知、 免疫防御等几乎所有的生物过程。因此, 深入研究其生物功能、 调控网络和开发应用等可能成为今后一段时间昆虫miRNA研究的重要内容。     

lncRNA调控畜禽抗病力性状研究进展

长链非编码RNA(longnon-coding RNA,lncRNA)是一类长度大于200个核苷酸的非编码RNA分子。lncRNA虽然不具备蛋白编码能力,但可通过转录调控、转录后调控及表观遗传修饰调控等方式影响基因的表达,进而影响性状的表型。在现代畜牧业生产中,除提高生长发育和产量性状外,研究免疫因子、细胞因子等抗病力相关指标及性状的调控机制,对提高和改善畜禽的健康、福利及公共卫生尤为重要。近年来,利用lncRNA研究鸡(Gallus gallus)、猪(Sus scrofa)、牛(Bos taurus)等重要畜禽的抗病力性状的调控机制取得了一定进展,为将表观遗传标记应用于动物抗病遗传育种打下了一定的基础。本文介绍了lncRNA的生物学功能和产生机制,着重阐述了lncRNA对畜禽抗病力性状的调控作用及研究进展,以期为lncRNA在畜禽抗病遗传育种方面的研究及应用提供科学依据。     

癌变重编程的表观遗传调控机制研究进展

肿瘤发生和恶化转化过程中导致细胞的异常编程,并由此产生了肿瘤干细胞。肿瘤干细胞具有自我更新和可塑性潜能,是肿瘤起始、转移、耐药和复发的根源。因此,对肿瘤重编程和肿瘤干细胞的研究具有重大科学价值和临床意义。表观遗传调控在肿瘤重编程中发挥重要作用。染色质重塑复合物、组蛋白修饰和非编码RNA等表观遗传机制都参与了癌变重编程。这些表观遗传调控可以调控肿瘤干细胞的自我更新和分化形成新肿瘤的能力。表观遗传调控癌变重编程、肿瘤干细胞自我更新的调控以及针对肿瘤干细胞表观调控机制的靶向治疗等问题,已成为肿瘤生物学研究的重点。现就染色质重塑复合物、组蛋白修饰和非编码RNA对癌变重编程和肿瘤干细胞调控的研究进展进行了综述。     

Genomic imprinting and evolution of insect societies

Reproductive division of labor is a hallmark of social insect societies where individuals follow different developmental pathways resulting in distinct morphological castes. There has been a long controversy over the factors determining caste fate of individuals in social insects. Increasing evidence in the last two decades for heritable influences on division of labor put an end to the assumption that social insect broods are fully totipotent and environmental factors alone determine castes. Nevertheless, the genes that underlie hereditary effects on division of labor have not been identified in any social insects. Studies investigating the hereditary effects on caste determination might have overlooked non-genetic inheritance, while transmission to offspring of factors other than DNA sequences including epigenetic states can also affect offspring phenotype. Genomic imprinting is one of the most informative paradigms for understanding the consequences of interactions between the genome and the epigenome. Recent studies of genomic imprinting show that genes can be differentially marked in egg and sperm and inheritance of these epigenetic marks cause genes to be expressed in a parental-origin-specific manner in the offspring. By reviewing both the eusocial Hymenoptera and termites, I highlight the current theoretical and empirical evidence for genomic imprinting in eusocial insects and discuss how genomic imprinting acts in caste determination and social behavior and challenges for future studies. I also introduce the new idea that genomic imprinting plays an essential role in the origin of eusociality.     

蜜蜂microRNA的研究进展

MicroRNA (miRNA)是一类长度为18~24 nt的内源性非编码小RNA分子,它能通过与靶标mRNA 分子互补结合抑制蛋白质翻译或导致 mRNA 降解,从而调控靶基因表达。蜜蜂是重要的社会性经济昆虫,一直是国际上热门的研究对象。迄今为止,通过各种生物技术在蜜蜂中发现已鉴定注册的miRNA共有218个,对蜜蜂miRNA的研究表明其在蜜蜂的胚胎发育、级型分化、劳动分工和免疫防御等方面可能具有重要的调控作用。本文就miRNA对蜜蜂蜂王和工蜂级型分化、哺育蜂和采集蜂劳动分工、舞蹈行为、脑部神经功能及免疫防御等方面调控作用的最新研究进展进行了综述,以期为进一步研究miRNA提供借鉴和参考。     

蜜蜂卵巢激活研究进展

蜜蜂Apis作为典型的社会性昆虫,最重要的特征就是生殖劳动分工。卵巢激活是蜜蜂发挥生殖能力的重要影响因素。本文对蜜蜂卵巢激活的影响因素、蜜蜂卵巢激活相关的基因表达及microRNA在蜜蜂卵巢激活过程中的可能作用进行了介绍,为研究蜜蜂级型分化和生殖劳动分工的分子机制提供依据。     

Caste-Specific and Sex-Specific Expression of Chemoreceptor Genes in a Termite

The sophisticated colony organization of eusocial insects is primarily maintained through the utilization of pheromones. The regulation of these complex social interactions requires intricate chemoreception systems. The recent publication of the genome of Zootermopsis nevadensis opened a new avenue to study molecular basis of termite caste systems. Although there has been a growing interest in the termite chemoreception system that regulates their sophisticated caste system, the relationship between division of labor and expression of chemoreceptor genes remains to be explored. Using high-throughput mRNA sequencing (RNA-seq), we found several chemoreceptors that are differentially expressed among castes and between sexes in a subterranean termite Reticulitermes speratus. In total, 53 chemoreception-related genes were annotated, including 22 odorant receptors, 7 gustatory receptors, 12 ionotropic receptors, 9 odorant-binding proteins, and 3 chemosensory proteins. Most of the chemoreception-related genes had caste-related and sex-related expression patterns; in particular, some chemoreception genes showed king-biased or queen-biased expression patterns. Moreover, more than half of the genes showed significant age-dependent differences in their expression in female and/or male reproductives. These results reveal a strong relationship between the evolution of the division of labor and the regulation of chemoreceptor gene expression, thereby demonstrating the chemical communication and underlining chemoreception mechanism in social insects.     

Soldier caste influences on candidate primer pheromone levels and juvenile hormone-dependent caste differentiation in workers of the termite Reticulitermes flavipes

Caste systems and the division of labor they make possible are common underlying features of all social insects. Multiple extrinsic factors have been shown to impact caste composition in social insect colonies. Primer pheromones are one type of extrinsic caste-regulatory factor; they are chemical signaling molecules produced by certain colony members to impact developmental physiology of recipient nestmates. However, only limited evidence exists regarding primer pheromones and their actions in eusocial termites. In previous research we identified two soldier-produced terpenes, γ-cadinene (CAD) and γ-cadinenal (ALD), as candidate primer pheromones of the lower termite Reticulitermes flavipes. In the present study we tested hypotheses related to CAD and ALD action in recipient individuals. We examined the influences of terminally developed soldier termites on (1) CAD and ALD levels and (2) caste differentiation in developmentally totipotent workers. Our findings show CAD and ALD (respectively) are caste stimulatory and inhibitory components of chemical blends present in soldier heads, ALD levels increase significantly (10.9×) in workers only in the presence of soldiers, and soldiers can reduce developmental-hormone response thresholds of workers, presumably via ALD action. These findings provide novel evidence supporting that CAD and ALD are authentic caste-regulatory primer pheromones in Reticulitermes.     

昆虫非遗传多型性研究进展

非遗传多型性是指同一基因型或同一基因组通过外界环境诱导可产生两种或者多种不连续表型的现象。该现象在昆虫中已有报道,如变态、季节性非遗传多型、社会性昆虫的等级制等。昆虫通过非遗传多型性做出应答,通过表型改变来适应环境并利用周围环境物质以达到躲避天敌从而进行生存繁衍的目的。因此,非遗传多型性是昆虫种类繁多、数量庞大的主要因素之一。近几十年来,非遗传多型性日益受到广泛关注,从最初对现象的描述,到诱导该现象产生的可能因素的实验验证,至目前大数据时代下利用二代测序技术、基因敲除和RNA干扰等技术揭示其分子机制。本文对近年来非遗传多型性在昆虫中的研究进展进行了总结,并对未来的趋势进行了展望。     

Physiological variation as a mechanism for developmental caste-biasing in a facultatively eusocial sweat bee

Social castes of eusocial insects may have arisen through an evolutionary modification of an ancestral reproductive ground plan, such that some adults emerge from development physiologically primed to specialize on reproduction (queens) and others on maternal care expressed as allo-maternal behaviour (workers). This hypothesis predicts that variation in reproductive physiology should emerge from ontogeny and underlie division of labour. To test these predictions, we identified physiological links to division of labour in a facultatively eusocial sweat bee, Megalopta genalis. Queens are larger, have larger ovaries and have higher vitellogenin titres than workers. We then compared queens and workers with their solitary counterparts-solitary reproductive females and dispersing nest foundresses-to investigate physiological variation as a factor in caste evolution. Within dyads, body size and ovary development were the best predictors of behavioural class. Queens and dispersers are larger, with larger ovaries than their solitary counterparts. Finally, we raised bees in social isolation to investigate the influence of ontogeny on physiological variation. Body size and ovary development among isolated females were highly variable, and linked to differences in vitellogenin titres. As these are key physiological predictors of social caste, our results provide evidence for developmental caste-biasing in a facultatively eusocial bee.     

蜜蜂——新兴的模式生物

蜜蜂作为具有重要经济价值和生态价值的社会性昆虫, 在诸如神经生物学和社会生物学等研究领域也具有很高的模型价值。蜜蜂基因组工程为深入认识蜜蜂的生物学特点,进一步发挥其在多个研究领域的模型价值奠定了分子基础。本文基于蜜蜂的生物学特点,介绍了蜜蜂作为模式生物所具备的优势,及其在学习和记忆、劳动分工、级型分化、免疫等热点领域的研究价值。通过总结和展望国内外蜜蜂生物学研究形势,呼吁国内相关各学科开展合作研究。     

Rapid Transition towards the Division of Labor via Evolution of Developmental Plasticity

A crucial step in several major evolutionary transitions is the division of labor between components of the emerging higher-level evolutionary unit. Examples include the separation of germ and soma in simple multicellular organisms, appearance of multiple cell types and organs in more complex organisms, and emergence of casts in eusocial insects. How the division of labor was achieved in the face of selfishness of lower-level units is controversial. I present a simple mathematical model describing the evolutionary emergence of the division of labor via developmental plasticity starting with a colony of undifferentiated cells and ending with completely differentiated multicellular organisms. I explore how the plausibility and the dynamics of the division of labor depend on its fitness advantage, mutation rate, costs of developmental plasticity, and the colony size. The model shows that the transition to differentiated multicellularity, which has happened many times in the history of life, can be achieved relatively easily. My approach is expandable in a number of directions including the emergence of multiple cell types, complex organs, or casts of eusocial insects.