凡纳滨对虾TCP-1-eta基因的克隆及与耐寒性状的相关性

为研究凡纳滨对虾耐寒性状的分子机理,文章克隆了凡纳滨对虾的耐寒相关基因TCP-1-eta并对其与耐寒性状的关系进行了研究。首先,根据电子克隆所得序列设计引物,采用RT-PCR方法克隆得到长1 705 bp的TCP-1-eta基因序列,其中包括1 629 bp的完整开放阅读框,编码542个氨基酸残基。然后,运用荧光定量PCR对TCP-1-eta基因进行时空表达谱的分析:(1)组织表达分析结果显示,该基因在凡纳滨对虾肌肉组织中表达量最高;(2)不同低温处理下的表达结果显示,该基因在15℃开始呈上调表达,13℃时表达量最高;(3)13℃低温处理的表达结果显示,该基因在36 h内呈小幅上调表达,但36 h后表达量显著升高,48 h表达量达到0 h的150倍。进一步采用PCR-RFLP方法对216只凡纳滨对虾TCP-1-eta基因进行了SNP多态性检测,并将其与耐寒性状进行了关联分析。在该基因编码区第731碱基上发现C/T突变,方差分析结果表明该位点的不同基因型与耐寒力指标CDH(Cooling-degree hours)值相关(P<0.05),其中CC基因型的耐寒能力比TT基因型强。     

凡纳滨对虾TCP-1-Beta基因的克隆及其与耐寒性状的相关性

为研究凡纳滨对虾耐寒性状的分子机理,研究克隆了凡纳滨对虾耐寒相关基因TCP-1-Beta并对其与耐寒性状的关系进行了研究.根据电子克隆所得序列设计引物,采用RT-PCR方法克隆得到长1691 bp的凡纳滨对虾TCP-1-Beta基因序列,其中包括1608 bp的完整开放阅读框,编码535个氨基酸残基.然后,运用荧光定量PCR对TCP-1-Beta基因进行时空表达谱的分析:组织表达谱的结果显示,该基因在凡纳滨对虾肝胰腺组织中表达量最高;不同低温处理下的表达结果显示,在28℃和15℃处理下基因表达量无显著变化,13℃开始呈上调表达,11℃时表达量升高;13℃低温处理发现该基因在24h内表达量无显著变化,但36h后表达量显著升高.采用PCR-RFLP方法对216尾凡纳滨对虾TCP-1-Beta基因进行了SNP多态性检测,并将其与耐寒性状进行了关联分析.在该基因编码区第420碱基上发现G/A突变,方差分析结果表明该位点的不同基因型与耐寒力指标CDH值相关(P＜0.05),其中GG基因型的耐寒能力比AA基因型强.     

湖北海棠MhPR1a基因的克隆与表达特性分析

以水杨酸诱导的湖北海棠[ Malus hupehensis (Pamp.) Rehd.]全长cDNA文库和基因组DNA为模板,克隆其PR1a基因(MhPR1a)的全编码区序列,并对该序列进行生物信息学分析;在此基础上利用荧光定量RT-PCR技术对湖北海棠根、茎和叶中该基因的表达特性及经过10μmol·L-1ABA、4℃低温处理及苹果蚜虫(Aphis citricola van der Goot)侵染后叶中该基因的表达特性进行了测定.结果表明:克隆获得的MhPR1a基因全长518 bp,最大开放阅读框为492 bp,编码162个氨基酸残基;编码的蛋白质为酸性蛋白,其相对分子质量为16 960,等电点pI 5.46;其基因组DNA序列与cDNA序列完全一致,说明MhPR1a基因内部没有内含子.湖北海棠MhPR1a基因与苹果(M.domestic Borkh.)和沙梨[Pyrus pyrifolia( Burm.f.)Nakai] PR1基因的cDNA序列及其编码的氨基酸序列同源性均较高,其中cDNA序列的同源性均为97％,氨基酸序列的同源性分别为95％和97％;系统树也显示MhPR1a基因编码的氨基酸序列与苹果和沙梨的亲缘关系最近,聚为一类.MhPR1a基因编码的氨基酸序列具有SCP保守结构域,含有1个信号肽和6个保守的半胱氨酸残基.在湖北海棠的叶、茎和根中MhPR1a基因均能表达,在根中的表达量最高.10 μmol·L-1ABA和4℃低温处理48 h后均可诱导MhPR1a基因的表达,且相对表达量明显高于对照(处理0h);苹果蚜虫也可诱导MhPR1a基因的表达,说明MhPR1a基因在湖北海棠抵抗植食昆虫和低温胁迫的过程中可能发挥着重要作用.     

尼罗罗非鱼Orexin前体基因的克隆、组织分布及其在摄食调控中的表达

该文采用RT-PCR和cDNA末端快速扩增技术(rapid-amplification of cDNA ends,RACE)的方法,从尼罗罗非鱼(Oreochromis niloticus)下丘脑总RNA中获得了尼罗罗非鱼Orexin前体基因的cDNA全长序列。该cDNA全长648bp,其中开放阅读框的长423bp,编码Orexin前体蛋白为140个氨基酸,包括37个氨基酸的信号肽、43个氨基酸的Orexin-A、28个氨基酸的Orexin-B和末尾32个氨基酸组成的功能不详的多肽。采用Real-time PCR技术对尼罗罗非鱼Orexin前体基因的组织表达模式以及在摄食前后、饥饿和再投喂状态下的表达量变化进行了研究。结果显示,在脑部和外周等18个组织中都检测到了Orexin前体基因的表达,其中在下丘脑中表达量最高;在摄食前后,尼罗罗非鱼Orexin前体基因的表达量显著低于在摄食状态中;饥饿2、4、6和8d后,Orexin前体基因在下丘脑中的表达量与正常投喂组相比均显著升高,饥饿4d再投喂后,表达量又恢复至正常水平。这些结果表明,Orexin在尼罗罗非鱼摄食中可能有着重要的调节作用。     

家蝇伴侣蛋白TCP-1基因的序列分析、克隆及诱导表达

旨在对EST筛选得到的家蝇伴侣蛋白TCP-1(MD-TCPⅠ)基因进行序列分析,克隆其cDNA序列并在大肠杆菌中诱导表达。采用EST测序技术从已构建的家蝇幼虫cDNA质粒文库中筛选到MD-TCPⅠ基因,对其进行序列测定和分析。以该基因的cDNA文库质粒为模板,通过PCR的方法进行扩增,以pET-28a(+)为载体构建重组质粒,再转化到表达宿主大肠杆菌BL21(DE3)中,IPTG诱导表达。表达产物通过SDS-PAGE进行鉴定。结果显示,MD-TCPⅠ基因ORF全长753 bp,编码250个氨基酸,理论分子量27.07 kD;等电点5.92,该序列编码的蛋白属于热休克蛋白60家族的TCP。构建了正确基因序列MD-TCPⅠ重组表达质粒,重组蛋白在大肠杆菌BL21(DE3)中诱导表达。     

番茄LeNHX1基因植物过量表达载体的构建及表达分析

从番茄幼苗中提取RNA,根据NCBI中番茄LeNHX1基因序列设计引物,通过RT-PCR获得了番茄LeNHX1基因的cDNA序列,包含一个1 605 bp的开放阅读框,编码534个氨基酸。将cDNA序列连接到植物过量表达载体PBI121上,对所获得的重组质粒进行双酶切鉴定,结果表明,植物过量表达载体PBI121-LeNHX1已构建成功。半定量RT-PCR结果表明LeNHX1基因在根、茎和叶中均表达,盐、低温和脱落酸的诱导能提高LeNHX1基因的表达量,推测番茄LeNHX1基因在逆境应答中可能起着重要作用。     

小麦TaLEC1基因的克隆及其表达特性分析

为了探讨LEC1基因在小麦(Triticum aestivum L)非生物胁迫应答中的功能,该研究通过RT-PCR结合RACE技术克隆小麦TaLEC1基因,并采用qRT-PCR方法分析了该基因在小麦不同组织以及不同处理下的表达模式,为深入研究小麦LEC1基因在干旱、高温和高盐胁迫下的响应机制奠定基础。结果表明:(1)成功克隆到小麦TaLEC1基因,该基因cDNA序列全长为1 074 bp,其中5′端非编码区23 bp,开放阅读框为741 bp,3′端非编码区310 bp,编码246个氨基酸,具有典型的CBFD_NFYB结构域。(2)实时荧光定量分析显示,TaLEC1在不同组织间表达差异显著,10 d龄幼苗的叶中表达量最高。(3)TaLEC1基因可被植物激素ABA诱导而上调表达,属于ABA依赖型的表达调控通路。(4)PEG模拟干旱胁迫处理后的0.5～1 h,TaLEC1基因呈上调表达;42℃胁迫处理过程中,TaLEC1基因呈稳定上调表达趋势,并在胁迫处理后12 h和48 h时表达急剧上调,分别为对照的52.8倍和34.5倍;NaCl胁迫处理0.5 h时TaLEC1基因迅速上调表达。研究表明,小麦TaLEC1基因参与ABA依赖的胁迫响应,推测可能在小麦耐受高温胁迫和渗透胁迫过程中发挥着重要的脱水保护功能。     

珙桐中一个与低温相关基因的克隆及其表达研究

低温诱导膜蛋白是由低温诱导表达蛋白基因编码的一类疏水性蛋白,在植物抵御寒冷环境时起着一定的保护作用。从珙桐cDNA文库中获得一个未知基因（DiRCI）,该基因长539bp,其中包括174bp的开放阅读框,92bp的5′末端非编码区和273bp的3′末端非编码区,编码57个氨基酸残基蛋白,在氨基酸水平上同源性较高的是车前草的低温诱导膜蛋白（登入号：ACA66247.1）,其相似性为89.5%。半定量RT-PCR分析发现,25℃以上,该基因在珙桐各器官中基本上均未表达,但经8℃低温处理时,在成熟叶片、叶柄和成熟未萌发的种子中均有表达,但是在根中基本没有表达,进一步研究发现该基因在24h～48h内表达量增多并达到最高值,48h后其表达量逐渐减弱直至消失,说明该基因确实与低温诱导相关,从而初步推测该基因为低温诱导膜蛋白基因。该基因的克隆丰富和保存了珙桐基因资源,并为进一步研究冷胁迫的分子机制奠定了基础。     

珙桐中一个与低温相关基因的克隆及其表达研究(英文)

低温诱导膜蛋白是由低温诱导表达蛋白基因编码的一类疏水性蛋白,在植物抵御寒冷环境时起着一定的保护作用。从珙桐cDNA文库中获得一个未知基因(DiRCI),该基因长539bp,其中包括174bp的开放阅读框,92bp的5′末端非编码区和273bp的3′末端非编码区,编码57个氨基酸残基蛋白,在氨基酸水平上同源性较高的是车前草的低温诱导膜蛋白(登入号:ACA66247.1),其相似性为89.5%。半定量RT-PCR分析发现,25℃以上,该基因在珙桐各器官中基本上均未表达,但经8℃低温处理时,在成熟叶片、叶柄和成熟未萌发的种子中均有表达,但是在根中基本没有表达,进一步研究发现该基因在24h～48h内表达量增多并达到最高值,48h后其表达量逐渐减弱直至消失,说明该基因确实与低温诱导相关,从而初步推测该基因为低温诱导膜蛋白基因。该基因的克隆丰富和保存了珙桐基因资源,并为进一步研究冷胁迫的分子机制奠定了基础。     

Cloning of cDNA encoding rat TCP-1.

We have isolated and sequenced a cDNA encoding a rat homolog of the mouse t-complex polypeptide 1 (TCP-1). Its deduced gene product is a polypeptide of 556 amino acids, with a predicted Mr of 60,341. The similarity between mouse Tcp-1 and the rat homolog is about 94.0% at the nucleotide level and 97.1% at the amino acid level showing the evolutionary conservation of this protein. The similarity of the amino acid sequence of the rat TCP-1 is not significantly biased to any of those from wild (TCP-1B) or from t-haplotype mice (TCP-1A). From a comparison of deduced amino acid sequences of eukaryotic TCP-1 proteins, we found highly conserved domains. Southern blot analysis revealed that there are at least two similar sequences to Tcp-1 in the rat, one is a structural gene and the other seems to be a processed pseudogene.     

Comparative analysis of Hox paralog group 2 gene expression during Nile tilapia (Oreochromis niloticus) embryonic development

The hindbrain and pharyngeal arch-derived structures of vertebrates are determined, at least in part, by Hox paralog group 2 genes. In sarcopterygians, the Hoxa2 gene alone appears to specify structures derived from the second pharyngeal arch (PA2), while in zebrafish (Danio rerio), either of the two Hox PG2 genes, hoxa2b or hoxb2a, can specify PA2-derived structures. We previously reported three Hox PG2 genes in striped bass (Morone saxatilis), including hoxa2a, hoxa2b, and hoxb2a and observed that only HoxA cluster genes are expressed in PA2, indicative that they function alone or together to specify PA2. In this paper, we present the cloning and expression analysis of Nile tilapia (Oreochromis niloticus) Hox PG2 genes and show that all three genes are expressed in the hindbrain and in PA2. The expression of hoxb2a in PA2 was unexpected given the close phylogenetic relationship of Nile tilapia and striped bass, both of which are members of the order Perciformes. A reanalysis of striped bass hoxb2a expression demonstrated that it is expressed in PA2 with nearly the same temporal and spatial expression pattern as its Nile tilapia ortholog. Further, we determined that Nile tilapia and striped bass hoxa2a orthologs are expressed in PA2 well beyond the onset of chondrogenesis whereas neither hoxa2b nor hoxb2a expression persist until this stage, which, according to previous hypotheses, suggests that hoxa2a orthologs in these two species function alone as selector genes of PA2 identity.     

Structure and enzymatic removal of the chorion of embryos of the Nile tilapia

Dechorionation or partial digestion of the egg chorion is necessary for introducing embryonic stem cells into blastulas for chimera production and for harvesting blastulas. Several methods to digest the Nile tilapia Oreochromis niloticus chorion were tried and it was found that the chorions of most clutches of eggs were digested in <3 h using hatching medium [produced by allowing embryos to hatch in Hanks balanced salt solution (HBSS) in an incubator], or 2 mg ml⁻¹ pronase P6911 in 10% Ca/Mg free HBSS. The chorion of Nile tilapia possesses multiple lamellae as found in most teleost species that have been studied. It was found to be thinner than that of medaka Oryzias latipes and thicker than that of zebrafish Danio rerio . During natural hatching the chorion was digested from the inner surface, and tail movements helped to break the remaining chorion; however, chorion digestion has to be complete for experimental dechorionation, because digestion starts at the external surface. The zona radiata externa remained intact after experimental digestion with hatching media but was disrupted by pronase. Embryos dechorionated at the cleavage or blastula stage only survived for 2 or 3 days, but some dechorionated at the gastrula stage or early segmentation stage developed until the natural hatching time. If the chorion was partially digested at the cleavage or blastula stage, some embryos survived to hatch.     

Major histocompatibility complex class IIA and IIB genes of Nile tilapia Oreochromis niloticus: Genomic structure,molecular polymorphism and expression patterns

Major histocompatibility complex (MHC) is a large genomic region characterized by extremely high polymorphism, and it plays an important role in the immune response of vertebrates. In the present study, we isolated MHC class II genes from Nile tilapia in order to investigate the immune mechanism in tilapia and develop better strategies for disease prevention. Moreover, we cloned the full-length cDNA sequences of MHC IIA and IIB from Nile tilapia by the RACE approach. In addition, the genomic structure, molecular polymorphism and expression patterns of MHC II genes in Nile tilapia were also examined. Compared with that of other teleosts, Nile tilapia MHC class IIA contained four exons and three introns. The deduced amino acid sequence of the MHC IIA molecule shared 25.4–64.5% similarity with those of other teleosts and mammals. Six exons and five introns were identified from Nile tilapia MHC IIB, and the deduced amino acid sequence shared 26.9–74.7% similarity with those of other teleosts and mammals. All the characteristic features of MHC class II chain structure could be identified in the deduced sequences of MHC IIA and IIB molecules, including the leader peptide, α1/β1 and α2/β2 domains, connecting peptide and transmembrane and cytoplasmic regions, as well as conserved cysteines and N-glycosylation site. A total of 12 MHC IIA alleles were identified from six individuals. Four alleles originating from a single individual suggested that at least four MHC IIA loci existed. Moreover, 10 MHC IIB alleles were identified, among which four were detected in a single individual, suggesting that at least four MHC IIB loci existed. The expression of MHC IIA and IIB at the mRNA level in 10 types of normal tissues was determined using quantitative real-time PCR analysis. The highest expression level was detected in stomach and gill, whereas the lowest expression was detected in muscle and brain. Furthermore, MHC IIA and IIB were probably two candidate immune molecules involved in the resistance against streptococcosis, because their expression was significantly up-regulated in gill, kidney, intestine and spleen after the intraperitoneal injection of Streptococcus agalactiae.     

Exploring uncoupling proteins and antioxidant mechanisms under acute cold exposure in brains of fish

Exposure to fluctuating temperatures accelerates the mitochondrial respiration and increases the formation of mitochondrial reactive oxygen species (ROS) in ectothermic vertebrates including fish. To date, little is known on potential oxidative damage and on protective antioxidative defense mechanisms in the brain of fish under cold shock. In this study, the concentration of cellular protein carbonyls in brain was significantly increased by 38% within 1 h after cold exposure (from 28 °C to 18 °C) of zebrafish (Danio rerio). In addition, the specific activity of superoxide dismutase (SOD) and the mRNA level of catalase (CAT) were increased after cold exposure by about 60% (6 h) and by 60%-90% (1 and 24 h), respectively, while the specific glutathione content as well as the ratio of glutathione disulfide to glutathione remained constant and at a very low level. In addition, cold exposure increased the protein level of hypoxia-inducible factor (HIF) by about 50% and the mRNA level of the glucose transporter zglut3 in brain by 50%-100%. To test for an involvement of uncoupling proteins (UCPs) in the cold adaptation of zebrafish, five UCP members were annotated and identified (zucp1-5). With the exception of zucp1, the mRNA levels of the other four zucps were significantly increased after cold exposure. In addition, the mRNA levels of four of the fish homologs (zppar) of the peroxisome proliferator-activated receptor (PPAR) were increased after cold exposure. These data suggest that PPARs and UCPs are involved in the alterations observed in zebrafish brain after exposure to 18°C. The observed stimulation of the PPAR-UCP axis may help to prevent oxidative damage and to maintain metabolic balance and cellular homeostasis in the brains of ectothermic zebrafish upon cold exposure.     

尼罗罗非鱼生长激素及其受体的cDNA克隆与mRNA表达的雌雄差异

尼罗罗非鱼(Oreochromis niloticus)雌雄鱼生长差异明显,为了探讨其原因,本文采用RT-PCR方法克隆了尼罗罗非鱼生长激素(Growthhormone,GH)及其受体(Growth hormone receptor,GHR)的cDNA序列,并应用半定量RT-PCR方法比较了雌、雄尼罗罗非鱼垂体GHmRNA、肝脏GHRmRNA、肌肉GHRmRNA的表达差异。序列分析表明:GH开放阅读框为615bp,共编码204个氨基酸;GHR开放阅读框为1908bp,共编码635个氨基酸。以RT-PCR方法研究了GH、GHR在各组织的分布情况,结果表明:GH仅在垂体中检测到有表达,而GHR在所检测的18种组织中均有表达,其中以肝脏、肌肉、性腺、下丘脑、胸腺表达量较高。以半定量RT-PCR方法进一步比较了雌、雄尼罗罗非鱼垂体GHmRNA、肝脏GHRmRNA、肌肉GHRmRNA的表达量,结果表明:雄鱼垂体GHmRNA和肝脏GHRmRNA的表达量均显著高于雌鱼,肌肉GHRmRNA的表达量则无显著差异,推测垂体GHmRNA和肝脏GHRmRNA表达的雌雄差异是尼罗罗非鱼雌雄生长差异的主要原因之一。