中国水产科学  2021, Vol. 28 Issue (08): 948-958  DOI: 10.12264/JFSC2020-0694
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引用本文 

王美垚, 葛家春, 俞菊华, 唐永凯, 苏胜彦, 李建林, 李红霞, 李辉, 冯伟. 性成熟中华绒螯蟹脑、性腺的性别差异调控机制研究. 中国水产科学, 2021, 28(08): 948-958. DOI: 10.12264/JFSC2020-0694.
WANG Meiyao, GE Jiachun, YU Juhua, TANG Yongkai, SU Shengyan, LI Jianlin, LI Hongxia, LI Hui, FENG Wei. Sexual differentiation regulation mechanism in the brain and gonad of Eriocheir sinensis during reproduction. , 2021, 28(08): 948-958. DOI: 10.12264/JFSC2020-0694.

基金项目

江苏省青年科学基金项目(SBK2020044520);江苏省中华绒螯蟹种质创制与苗种繁育创新团队项目(20181123-1);江苏省现代渔业产业技术体系项目(JFRS-01-01);中国水产科学研究院淡水虾蟹遗传育种创新团队项目(2020TD36);淡水中心基本科研业务费项目(2018JBFR03);中华绒螯蟹良种选育项目(PZCZ201749).

作者简介

王美垚(1984‒), 女,博士,助理研究员,研究方向为水生动物遗传育种与分子生物学. E-mail: wangmy@ffrc.cn

通信作者

唐永凯,研究员,研究方向为水生动物遗传育种与分子生物学. E-mail: tangyk@ffrc.cn

文章历史

收稿日期:2020-06-30
修改日期:2020-12-23
性成熟中华绒螯蟹脑、性腺的性别差异调控机制研究
王美垚1,2,3,葛家春4,俞菊华1,2,3,唐永凯1,2,3,5,苏胜彦1,2,3,5,李建林1,3,李红霞1,3,李辉5,冯伟5,     
1. 中国水产科学研究院淡水渔业研究中心,农业农村部淡水渔业和种质资源利用重点实验室,江苏 无锡 214081;
2. 南京农业大学无锡渔业学院,江苏 无锡 214128;
3. 中国水产科学研究院淡水渔业研究中心 水生动物基因中心,江苏 无锡 214128;
4. 江苏省淡水水产研究所,江苏 南京 210017;
5. 上海海洋大学水产与生命学院,上海 201306
摘要:本研究采用比较转录组法探讨性成熟期中华绒螯蟹(Eriocheir sinensis)雌雄个体间脑、性腺的关键差异调控通路及繁殖调控的关键基因。结果表明,性成熟雌雄蟹其脑、性腺组织具有性别差异调控模式。脑内差异表达通路主要涉及信号转导、性激素调控及环境适应应答,性腺内关键差异调控通路主要涉及激素调控、氨基酸代谢调控等。脑内繁殖调控关键基因主要涉及发育及内稳态调控等,如III型纤连蛋白域结合蛋白3a (FNDC3A)、反式甲酸2 (INF2)、神经胶质蛋白(NRG)、假苷酸合酶7同系物(PUS7)、小泛素相关修饰子3 (SUMO3)、超氧化物歧化酶(SOD)等,性腺内关键调控基因主要涉及能源物质代谢、性细胞发育调控等,如甾醇调控原件结合蛋白1 (SREBF1)、卵泡刺激激素受体(FSHR)、表皮生长因子受体(EGFR)、丝/苏氨酸激酶4 (TSSK4)、胰岛素样生长因子2 mRNA结合蛋白3 (IGF2BP3)、磷脂酰肌醇3激酶调节亚基2 (PIK3R2)、胞质型多聚腺苷酸化原件结合蛋白(CPEB)等。本研究结果表明,性成熟河蟹雌雄个体间的脑、性腺具有差异调控模式,本转录组获得的差异调控通路及基因将为进一步开展河蟹繁殖调控研究提供丰富的理论信息。
关键词中华绒螯蟹        性腺    转录组    性别差异    
Sexual differentiation regulation mechanism in the brain and gonad of Eriocheir sinensis during reproduction
WANG Meiyao1,2,3,GE Jiachun4,YU Juhua1,2,3,TANG Yongkai,1,2,3,5,SU Shengyan1,2,3,5,LI Jianlin1,3,LI Hongxia1,3,LI Hui5,FENG Wei5    
1. Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, China;
2. Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214128, China;
3. Aquatic Animal Genome Center of Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214128, China;
4. Freshwater Fisheries Research Institute of Jiangsu Province, Nanjing 210017, China;
5. College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China
Abstract: Eriocheir sinensis is an important catadromous aquatic species in Yangtze River, China, and is one of the leading species for special new variety breeding. E. sinensis is popular both in domestic and foreign markets for its unique flavor. The breeding industry for this fish has developed prosperously; however, precocity is still a hindrance on development. Undoubtedly, researching the physiological regulation mechanism of gonadal development would benefit the E. sinensis breeding industry. However, there are few studies on the mechanism of sexual differentiation regulation in crabs during reproduction. In this study, we performed comparative transcriptome analysis to explore the key differential regulatory pathways in the brains and gonads of male and female E. sinensis during reproduction, as well as the common regulatory genes in these two tissues for reproductive regulation. The results indicated a substantial sexual differentiation regulation mode in the brains and gonads of sexually mature males and females of E. sinensis. The differential regulatory pathways in the brain involved signal transduction, sexual hormone regulation, and adaptive response to environment. The key regulatory pathways in the gonad involved hormone regulation and amino acid metabolism regulation. The key genes relevant to reproduction regulation in the brain were primarily those involved in development and homeostasis regulation, such as FNDC3A, INF2, NRG, PUS7, SUMO3, and SOD. Key regulatory genes in the gonad were primarily those involved in energy substance metabolism and sexual cell development, such as SREBF1, FSHR, EGFR, TSSK4, IGF2BP3, PIK3R2, and CPEB. These results provide theoretical information for further exploration into sexual differentiation regulation in the reproduction of E. sinensis, theoretical references for gender control techniques, and theoretical basis for promoting the development of the E. sinensis breeding industry.
Key words Eriocheir sinensis     brain    gonad    transcriptome    sexual differentiation    

中华绒螯蟹(Eriocheir sinensis)隶属于节肢动物门(Arthropoda), 甲壳纲(Crustacea), 十足目(Decapoda), 方蟹科(Grapsidae), 绒螯蟹属,是我国长江中重要的洄游生物[1-2]。由于环境污染、过度捕捞等,其野生资源遭到了严重破坏[3]。中华人民共和国农业农村部于2019年2月1日发表公告禁止长江流域野生中华绒螯蟹生产性捕捞,中华绒螯蟹资源恢复及保护工作刻不容缓。自20世纪70年代我国水产科研人员开始探索中华绒螯蟹的人工养殖,至今河蟹养殖面积已达1000万亩左右,已形成较成熟的产业链[4], 但仍存在许多问题,如性早熟仍旧是阻碍中华绒螯蟹养殖业发展的重要问题,给渔民带来严重经济损失,同时也导致中华绒螯蟹种质资源退化[5], 因此探讨中华绒螯蟹性腺发育的生理调控机制对更好促进中华绒螯蟹养殖业的发展具有重要意义。

雌雄异形是动物界普遍存在的现象,其指的是雌雄个体在形态、生理等方面存在显著差异[6]。Assis等[7]自2012年最早开始了节肢动物果蝇的雌雄异形研究。近几年,在蟹类中也已逐渐开展了一些雌雄异形的研究,涉及红海寄居蟹(Clibanarius signatus)、拟穴青蟹(Scylla paramamosain)、日本绒螯蟹(Eriocheir japonica)等,报道了其雌雄个体在生长性能、形态等方面的差异性,以及地理位置、季节变化等环境因子对该差异的影响作用[8-11], 但未见有关中华绒螯蟹繁殖的雌雄差异性调控机制研究报道。脑是神经信号调控的重要器官,其分泌产生的神经激素如促性腺激素释放激素等与特异性受体结合后刺激促性腺激素的产生和释放,调控生殖细胞的发育及性成熟,对生殖活动发挥重要的调控作用[12]。甲壳动物的繁殖活动以及性腺发育受到多种组织及器官的精细调控,包括X-器官窦腺复合体、大颚器官、Y-器官、脑、胸腹神经团以及性腺等[13-17]。性腺可以产生生殖细胞,是甲壳动物繁殖活动的基础,另一方面,性腺具有内分泌功能,可以分泌产生类固醇性激素,包括17β-雌二醇、孕酮等雌激素以及促雄性腺激素等雄激素,这些性激素由性腺分泌至外周血淋巴中,进而调控机体生理活动。与此同时,性腺还可以对自身发育发挥调控作用。其可以分泌产生转化生长因子β、胰岛素样生长因子结合蛋白等因子。转化生长因子β及其受体可以调控睾酮及黄体酮的含量,进而调控性腺发育[18], 胰岛素样生长因子结合蛋白对卵巢细胞分裂、卵子成熟等发挥调控作用[19]。鉴于脑与性腺在中华绒螯蟹的繁殖与性腺发育中的重要调控作用,本研究开展了性成熟雌、雄中华绒螯蟹脑、性腺组织的比较转录组研究,揭示中华绒螯蟹雌、雄个体中枢神经组织对性腺发育的差异性调控通路及基因,以及雌雄个体性腺组织的差异性调控通路及基因,旨在为进一步探讨中华绒螯蟹雌雄差异调控机制奠定理论基础,更好地促进中华绒螯蟹繁养殖业的发展。

1 材料与方法 1.1 实验动物

实验动物为即将繁殖的卵巢发育至V期的性成熟中华绒螯蟹雌蟹及即将繁殖的性成熟雄蟹。此时雌蟹卵巢呈酱紫色,卵粒大小均匀; 雄蟹精巢未有明确分期,繁殖前,精巢显著膨大,其内已有精子从生精小管内释放,可见留有空腔。实验蟹均捕自江苏诺亚方舟农业科技有限公司同一成蟹养殖池塘。

1.2 样品采集

3只性成熟雌蟹平均体重(205±1.3) g, 平均壳长(6.5±0.8) cm, 3只性成熟雄蟹平均体重(253± 2.5) g, 平均壳长(7.1±0.6) cm, 分别采集其脑、性腺(卵巢及精巢)组织迅速置于液氮内,而后转入−80 ℃冰箱内以备后续实验。

1.3 RNA的提取与检测、文库构建及测序

参照RNAiso reagent (TaKaRa, 日本)说明书提取中华绒螯蟹脑、性腺组织总RNA。使用1%琼脂糖凝胶电泳检测RNA降解程度,用重组DNAaseI (TaKaRa, 日本)试剂盒去除基因组DNA。以Nanodrop (Implen, 美国)检测RNA的纯度,以Qubit 2.0 (Life Technologies, 美国)测定RNA浓度并用 Agilent2100生物分析系统(Agilent Technologies, 美国)检测RNA的完整性。用带有Oligo (dT)的磁珠富集真核生物的mRNA; 加入打断试剂将mRNA随机打断成小片段,利用六碱基随机引物分别合成一链、二链cDNA。经纯化的双链cDNA再行末端修复,并在3′末端连接碱基A及测序接头,通过磁珠富集所需片段,而后进行PCR扩增,使用AMPure XP beads磁珠纯化产物,构建好的文库用Agilent 2100生物分析系统(Agilent technologies, 美国)进行检测,然后应用Illumina HiSeqTM 2500进行转录组测序。文库构建、测序、装配及生物信息学分析由诺禾致源生物科技有限公司完成。

1.4 测序数据过滤与装配

使用NGS QC TOOLKIT v2.3.3软件(Roche, Pleasanton, CA, 美国)对测序获得的原始数据进行过滤,去除带有接头序列的reads, 去除含有未确定碱基信息大于10%的reads, 以及低质量、被污染reads等[20]。然后用Trinity软件(Broad Institute, Cambridge, 英国)进行装配[21]

1.5 基因功能注释

采用BLAST算法计算基因的相似性,然后依次与NR、NT、SwissProt和KOG数据库进行比对,获得具有最高相似性的蛋白的注释信息[22-23]。采用Blast2GO软件进行GO注释[24]。利用KAAS预测进行KEGG通路分析。

1.6 基因的表达水平及差异表达富集分析

使用Bowtie2 (http://bowtie-bio.sourceforge. net/bowtie2/manual.shtml)[25]和eXpress软件(http:// www.rna-seqblog.com/express-a-toolfor-quantification-of-rna-seq-data/)[26]来计算基因的表达丰度,将Bowtie2软件得到的结果进行FPKM转换从而计算基因的表达水平[27]。用DESeq软件(http:// bioconductor. org/packages/release/bi-oc/html/DESeq. html)进行基因的差异表达分析[28]。筛选条件为P<0.05, |log2Foldchange|>1。脑以及性腺组织的Foldchange值分别是雄蟹与雌蟹脑组织、雄蟹精巢与雌蟹卵巢的基因表达水平之比。以差异表达基因进行KEGG通路富集分析,以P<0.05为筛选条件,然后以−lgP筛选出脑以及性腺组织的top10 KEGG通路,−lgP越小,差异越显著,若筛选获得的通路数目不足10条,则筛选后通路将全部展示。

1.7 实时荧光定量PCR对差异表达基因的验证

从脑、性腺转录组数据分别随机选取6个差异表达基因,以Primer Premier 5软件设计引物,采用ABI 7500 (ABI, 美国)实时荧光定量PCR系统开展荧光定量PCR验证实验。以β-actin作为内参基因,采用2–ΔΔCT法进行分析[29]。实验反应程序为: 95 ℃, 30 s; 然后95 ℃, 5 s, 60 ℃反应34 s, 进行40次循环; 最后72 ℃反应50 s。每个样品设立3个重复。

1.8 统计分析

实验数据采用SPSS21.0进行统计分析,数据以平均值±标准差($\bar{x}\pm \text{SD}$)表示,采用t检验方法,差异显著性水平为0.05.

2 结果与分析 2.1 转录组测序和装配统计

本研究分别获得了平均约65173833和65627311的雌、雄蟹脑组织raw reads, 平均约59685755和59258896的卵巢和精巢组织raw reads。相应地,得到了平均约65130003和65606817的雌、雄蟹脑组织clean reads, 平均约59651566和59224635的雌、雄蟹性腺组织clean reads。雌、雄蟹性腺、脑组织的Q20均大于96%。共获得了664618个unigene, 平均长度为674 bp, 其中长度为500~1000 bp之间的unigene共176315个,长度大于1000 bp的unigene为108222个,N50值为874 bp。

2.2 GO功能注释

将转录组信息与GO数据库进行比对,注释到了生物过程、细胞组分、分子功能3个亚类中的56个条目中(图1)。在“生物过程”亚类中,得到最显著注释的条目依次为“细胞过程”“代谢过程”“单一生物体过程”以及“生物学调控”; 在“细胞组分”亚类中,得到最显著注释的条目依次为“细胞”“细胞组分”“细胞膜”和“细胞器”; 在“分子功能”亚类中,得到最显著注释的条目依次为“结合”“催化活性”和“转运体活性”。

2.3 雌雄蟹脑与性腺的差异富集top KEGG

分别获得了中华绒螯蟹雌雄个体的脑、性腺组织繁殖调控相关的top KEGG通路。如图2所示,脑组织top KEGG涉及信号转导(通路1~3)、性激素调控(通路4~6)以及环境适应应答(通路7)。如图3所示,性腺组织中繁殖调控相关的top KEGG通路主要涉及激素调控(通路1、5~8)和氨基酸代谢(通路2~4)。

2.4 雌雄蟹脑、性腺中繁殖调控关键基因

在本研究中,通过差异表达基因分析,本研究获得了中华绒螯蟹雌雄个体脑以及性腺组织中繁殖调控关键基因(表1)。

2.5 qRT-PCR验证

本研究从中华绒螯蟹脑、性腺组织转录组信息中分别随机选取了6个差异表达基因进行qRT-PCR验证,分别是脑组织内的基因: E3泛素连接酶(KCMF1)、固醇调节元件结合蛋白1(SREBF1)、帕林蛋白(MIG-6)、5′-3′核糖核酸外切酶2同系物(RAT1)、酰基辅酶A结合蛋白(DBI)、瞬时受体电位阳离子通道蛋白(PAIN)以及性腺组织内的水通道蛋白9 (AQP9)、葡聚糖内切酶(CELA)、载脂蛋白D (APOD)、肌钙腔蛋白(SRL)、神经胰蛋白酶(PRSS12)、心钠素转换酶(CORIN)等共12个基因,引物信息见表2。如图4所示,脑、性腺组织的差异表达基因相对表达水平与转录组中相应基因表达水平基本一致,可以认为本转录组数据是可信的。

图1  中华绒螯蟹脑与性腺转录组GO注释GO注释包括三大亚类: 生物过程(粉色)、细胞组分(绿色)和分子功能(蓝色). 横轴为条目名称,纵轴为基因数目. Fig. 1  GO annotation of brain and gonad transcriptome of Eriocheir sinensis GO terms can be classified into three categories: biological process (pink), cellular component (green), and molecular function (blue). The horizontal axis indicates gene names in each term, and the vertical axis indicates numbers of genes in each term.
图2  中华绒螯蟹脑内top KEGG通路 Fig. 2  Top KEGG pathways enriched in brain of  Eriocheir sinensis
图3  中华绒螯蟹性腺内繁殖调控相关的KEGG通路 Fig. 3  KEGG pathways relevant to reproduction regulation enriched in gonad of Eriocheir sinensis
3 讨论 3.1 脑内top KEGG通路分析

长时程抑制是指在特定突触刺激下,如长时间低频输入等导致突触传导强度长期下降的生物学过程,涉及复杂的信号转导及受体循环过程。长时程抑制因其自身特性使其参与突触可塑性的调控,同时也对生物体的学习、记忆等均具有重要调节作用[30]。中华绒螯蟹是洄游型生物,其在繁殖期需进行降海洄游以促使性腺发育成熟,也可能因为繁殖期内雌雄蟹脑组织相关学习记忆通路在此过程中发挥重要调控作用,因而出现差异性表达。胆碱能突触是以乙酰胆碱为神经递质的神经系统中重要的信号传导通路,是生物体外周神经系统信号转导的重要通道,对生物体大脑的学习、以及记忆等同样发挥着重要的调控作用[31]。血清素通路是以5-羟色胺(又名血清素)为神经递质的一种生物体内抑制性神经递质信号传导方式,对于机体各类细胞代谢过程包括增殖、分化、发育等具有重要调控作用。作为一种抑制性神经递质,其可以抑制兴奋信号传导从而维护神经系统兴奋传导内稳态,保护机体免受神经系统过度兴奋所产生的有害作用。对学习记忆、运动、内分泌等都发挥积极调控作用[32]。研究表明,血清素还对生物体妊娠期胰岛素细胞生成、血糖水平等发挥重要调节作用[33]。本研究中,其在雌雄亲蟹脑组织内的差异性表达体现了其性别差异性调控作用。研究表明,生物体雌雄个体在神经系统信号转导调控方面存在显著的性别差异,这也导致二者在繁殖行为等方面出现差异[34]。本研究中,性成熟亲蟹雌雄个体脑组织中的各类神经突触信号通路出现差异表达,体现了二者的性别差异性调控模式。

表1  中华绒螯蟹脑、性腺转录组关键调控基因 Tab. 1 Key regulatory genes in brain and gonad transcriptome of Eriocheir sinensis
表2  实时荧光定量PCR所用引物序列 Tab. 2  The primers of the genes used for real-time RT-PCR
图4  差异表达基因的qRT-PCR验证横轴为基因名称,纵轴为相对表达水平. Fig. 4  Validation of DEGs by qRT-PCR The horizontal axis shows gene names. The vertical axis shows relative expression.

本研究中昼夜节律这一环境适应调控通路出现了显著差异表达。昼夜节律是生物体体内的生物钟对外界信号因子所作出的一种内源性调控应答机制,从而使机体的内分泌以及行为节律与外界信号同步,是机体对外界环境的一种适应性应答[35]。研究表明,甲壳动物幼体释放受到机体内源昼夜节律调控因子的影响而具有周期性[36]。鉴于中华绒螯蟹的繁殖特性,因而昼夜节律调控通路在性成熟中华绒螯蟹具有雌雄差异性调控模式。

3.2 性腺内top KEGG通路分析

卵母细胞成熟是一个由多基因调控的复杂的生理过程,涉及黄体生成激素、信使环磷酸腺苷、钙离子、表皮生长因子等多种因子。它是指初级卵母细胞停止在第二次减数分裂中期从而形成次级卵母细胞这一生理过程,是雌性个体卵子形成的必经过程,继而也是生物体正常繁殖的关键所在[37]。在水产生物,如斑马鱼(Danio rerio)、褐点石斑鱼(Epinephelus coioides)等繁殖调控研究中,都体现了其对生物体繁殖的重要作用[38-39]。本研究中,成熟中华绒螯蟹雌雄个体性腺内该通路出现显著差异表达,体现了它对卵巢发育及雌雄个体正常繁殖的重要调控作用。

促性腺激素释放激素对性类固醇激素、促性腺激素水平等均具有调控作用,可以诱导配子的释放,对生物体的性腺发育、性行为、生殖活动等均发挥重要的调节功用[40]。在蓝蟹(Portunus pelagicus)上的研究表明,其可以促进生殖细胞在睾丸中的成熟,提高精子产量[41]。本研究中,促性腺激素释放激素通路在中华绒螯蟹雌雄成体生殖腺中出现了显著差异表达,体现了其对于雌雄个体性腺发育、繁殖等的重要调控作用。

卵巢类固醇,如孕酮、17β-雌二醇等,是雌性生物体卵巢内的重要性激素。它对子宫功能、妊娠的建立和维持以及乳腺发育至关重要。在罗氏巨臂虾(Macrobrachium rosenbergii)的研究表明,卵巢类固醇在促进虾体卵黄的形成、卵母细胞的生长及成熟上发挥了重要的调控作用[42]。在斑马鱼繁殖调控研究也表明,卵黄类固醇是其卵母细胞成熟的必需物质[43]。本研究中,雌蟹卵巢类固醇合成通路的显著上调表达体现了其对雌性繁殖的重要调控作用。

催乳素是一种多肽激素,具有广泛的生理调节功能,对渗透调节、哺乳、生殖、生长和发育、内分泌等均具有重要调控作用,同时它还参与调节睾丸、卵巢等的功能[44]。在蓝鳃鱼(Lepomis macrochirus)的亲代抚育行为研究表明,催乳素可以促进成鱼的养育行为[45]。在本研究中,中华绒螯蟹雌雄个体性腺中催乳素调控通路出现了显著差异表达,是其对中华绒螯蟹繁殖行为等发挥关键调控作用的重要体现。

3.3 脑与性腺内的繁殖调控基因分析

本研究中,脑内FNDC3AINF2NRGPUS7SUMO3SOD等基因对雌雄蟹繁殖、性腺发育等发挥了重要的性别差异性调控作用。FNDC3A介导精细胞与支持细胞的黏附作用,在精子发生中发挥重要调节作用[46]。在本研究中,该基因在雄蟹上的表达水平高于雌蟹,体现了其重要的调控作用。INF2介导肌动蛋白的聚合与解聚,从而调节膜蛋白的运输,对信号转导发挥调控作用[47]。研究表明,INF2的表达水平将会影响胚胎的正常发育以及妊娠[48]。本研究中,繁殖期雌蟹脑、性腺中该基因表达水平均显著高于雄蟹,也体现了其对雌蟹的重要调控作用。NRG对于胚胎发育过程中的神经和胶质细胞黏附发挥调控作用,是血脑屏障形成中不可或缺的组成部分[49]。研究表明,神经胶质细胞突变会降低雌性的生殖能力[50]。本研究中,性成熟雌蟹中该基因的表达水平,也体现了其对于雌雄蟹繁殖的差异性调控作用。

本研究中,性腺内SREBF1FSHREGFRTSSK4IGF2BP3PIK3R2CPEB等基因对雌雄蟹繁殖及性腺发育等发挥了重要的差异性调控作用。SREBF1对于脂肪酸的转录、胆固醇合成等均发挥调控作用,是维护脂质内稳态的必需转录激活子[51]。脂类物质为中华绒螯蟹繁殖期重要营养物质,在能量供给方面,脂类物质是中华绒螯蟹胚胎发育的主要供给者。脂类营养物质的缺乏将会影响胚胎的正常发育,甚至引起死亡等[52]。本研究中,性成熟雌蟹脑及性腺中该基因的表达水平高于雄蟹,可能是由于雌蟹较高的能量需求以及较旺盛的脂代谢所形成的。促性腺激素释放激素通路对于生物体繁殖发挥着极其重要的作用。表皮生长因子受体(EGFR)作为该通路的重要启动基因,对生物体性成熟发挥了重要作用[53]。在虎虾(Penaeus monodon)的性腺转录组研究中,也发现了其对于机体性成熟的重要调控作用[54]。本研究中,其在中华绒螯蟹雌雄个体性腺发育、繁殖等也发挥了重要的调控作用。在斑马鱼的研究表明,胰岛素样生长因子2 mRNA结合蛋白3 (IGF2BP3)与位于其卵母细胞动物极的细胞周期蛋白B1的3′非翻译区相结合。其可以抑制未成熟卵母细胞内的翻译,对卵母细胞的成熟发挥调控作用[55]。在本研究中,其在雌蟹卵巢中的显著上调表达体现了其对雌蟹繁殖的重要调控作用。研究表明,颗粒细胞在卵母细胞的发育中发挥着重要的调控作用胞质型多聚腺苷酸化原件结合蛋白(CPEB), 是卵母细胞中一种mRNA结合蛋白,通过与mRNA结合从而调控基因的翻译[56]。研究表明,它对于脊椎动物和无脊椎动物卵巢发育、卵子发生等都发挥着重要的调控作用[57-58]。在本研究中,它在雌蟹卵巢中的显著上调表达,体现了其对雌性个体性腺发育的重要调控作用。

4 结论

综上所述,本研究表明性成熟雌雄蟹在脑、性腺内具有差异显著的性别调控模式。脑内差异调控通路主要涉及信号转导、性激素调控及环境适应应答。性腺内关键差异调控通路主要涉及激素调控、氨基酸代谢调控等。脑内繁殖调控关键基因主要涉及发育及内稳态调控等,如FNDC3AINF2NRGPUS7SUMO3SOD等。性腺内关键调控基因主要涉及能源物质代谢、性细胞发育调控等,如SREBF1FSHREGFRTSSK4IGF2BP3PIK3R2CPEB等。本研究为进一步深入探讨中华绒螯蟹雌雄个体繁殖差异调控机制提供基础信息,为今后更好开展中华绒螯蟹性别控制技术提供理论参考,为更好促进中华绒螯蟹养殖业的发展提供理论积累。

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