毛白杨真菌胁迫下miRNA靶基因预测和生物信息分析

目前,关于杨树在真菌胁迫下其mi RNAs对基因的调控作用研究较少。准确快速地预测并鉴定mi RNA靶基因,对揭示真菌胁迫下mi RNAs在基因调控中的作用至关重要。该文根据mi RNA的进化保守性,通过靶基因预测软件ps RNATarget,以已知的毛果杨mi RNAs为探针,与毛白杨真菌胁迫下转录组的基因序列比对,找到其中347个mi RNAs的772个靶基因,分别编码与植物激素信号传导、植物病原互作、谷胱甘肽代谢等与植物抗病密切相关的蛋白。mi R393通过转录后水平作用于靶基因,调节生长素信号以响应多种外界刺激。该研究发现了mi R393的11个靶基因,主要参与生长素介导的信号通路;其中6个靶基因(SD1-13、CYP83B1、AFB2、TIR1、AFB3和PSBR)存在差异表达,这些基因是研究mi R393的生物学功能的关键候选基因。     

植物MicroRNA介导的基因调控在作物改良中的应用潜能

植物Micro RNAs(mi RNAs)是长度约22个核苷酸的內源、单链、非编码、小分子RNA,通过降解或抑制靶m RNA介导转录后沉默。随着高通量测序技术及各种研究技术的进步,越来越多的micro RNA被测序和验证,为利用基因工程手段进行作物改良提供了丰富的候选基因资源。综述了mi RNAs在生物胁迫、非生物胁迫和植物生长发育等方面的最新研究进展,同时分析了mi RNAs介导的基因调控在作物改良中的应用潜能,并介绍了几种基于mi RNA作用机制的植物基因工程改良作物的转基因新技术,如靶基因RNAi,人工mi RNAs(ami RNAs),Target Mimics(TM),超表达mi RNA-resistant tagerts;也讨论了基于mi RNA作用机制的转基因技术所面临的风险和挑战。     

大豆miR172家族成员序列及表达模式初步分析

Micro RNAs(miRNAs)在植物的生长发育以及植物对环境的适应方面发挥了重要的作用,成为近几年研究的热点。mi R172家族是一个保守的mi RNA家族,之前的研究表明mi R172的作用涉及生长期过渡、闭花受精、花器官发育、开花时间调控等方面。但是到目前为止,人们对大豆mi R172家族的了解还不是很清楚。本实验通过mi RBase、PLACE数据库及DNAman软件对gma-mi R172家族成员的前体序列、成熟序列、启动子序列进行比较分析,发现gma-mi R172家族成员成熟序列虽然高度保守,但前体序列具有一定的差异,这可能导致了各成员的功能差异;启动子分析显示其启动子含有光反应原件和多种非生物胁迫响应元件,推测其可能参与大豆的开花调控和逆境胁迫响应。通过实时定量PCR分析了大豆mi R172成员的组织特异性表达情况。利用PMRD数据库对gma-mi R172的靶基因进行了生物信息学分析,获得了7个AP2-like类转录因子,参与花器官发育、开花时间调控及非生物胁迫响应的方面。上述结果初步分析了大豆mi R172家族的功能与靶基因,对今后进一步分析研究大豆mi R172家族及其靶基因打下了基础。     

基于瞬时表达系统的水稻miRNA靶基因快速验证系统的建立

旨在建立一种准确且快速的基于瞬时表达系统的水稻mi RNA靶基因验证系统,为研究水稻miRNAs的生物学功能奠定基础。已有研究证实osa-miR169o剪切靶基因OsNF-YA4(LOC_Os03g48970.1)的mRNA,以此为参照,在烟草和水稻原生质体瞬时表达系统中将miR169o前体基因分别与LUC表达载体、LUC-48970和LUC-48970m3融合表达载体瞬时共表达,通过CCD活体成像和Luminometor分析了共表达后LUC活性的动态变化。利用茎环qRT-PCR对miR169o的表达水平进行分析,获得靶基因验证的适合体系。在水稻原生质体体系中,LUC活性和miR169o表达水平在原生质体转化后逐渐增高;24 h时LUC活性最高,相应miR169o表达水平上升10倍左右。综合分析,在原生质体转化后24 h-36 h为适宜检测时间段。在烟草瞬时表达体系中,农杆菌注射72 h后LUC活性最强,而miR169o的表达在48 h后即可上调20倍。因此,农杆菌注射后48 h-72 h为适宜检测时间段。本系统为水稻miRNA靶基因的验证提供了一种简便、快速,且更接近于体内真实情况的实验方法。     

microRNA在植物生长发育中的研究进展

microRNA(miRNA)是一类广泛存在于植物体内,长约20-25个核苷酸的内源性非编码小分子RNA,通过定向降解靶基因mRNA和抑制其翻译,从而在转录后水平控制靶向基因的表达来调控多种多样的生物功能,包括植物的生长发育、生殖和对逆境胁迫的响应。已有的研究表明,miRNA及其靶基因不仅在植物的时序转换中是一个关键调控因子,也在茎尖发育、叶形态建成、花器官发育和开花时间等过程中发挥着重要调控作用。重点介绍mi RNA在调控植物生长发育过程以及发育可塑性过程中的研究进展,并对植物miRNA研究中有待进一步阐明的问题进行了探讨和展望,以期为深入解析miRNA在调节植物组织和器官模式中的功能,以及植物形态多样性中的作用和分子调控网络提供参考。     

意大利蜜蜂幼虫肠道在球囊菌胁迫后期的差异表达微小RNA及其靶基因分析

【目的】蜜蜂球囊菌Ascosphaera apis(简称球囊菌)是一种特异性侵染蜜蜂幼虫肠道的致死性真菌病原。微小RNA(microRNA,mi RNA)是一种在转录后水平对m RNA进行负调控的关键调控因子。本研究旨在对意大利蜜蜂Apis mellifera ligustica(简称意蜂)幼虫肠道在球囊菌胁迫后期的差异表达mi RNAs(DEmiRNAs)及其靶基因进行深入分析,为揭示DEmiRNAs在胁迫应答中的作用提供重要信息。【方法】利用small RNA-seq(s RNA-seq)技术对正常及球囊菌侵染的意蜂6日龄幼虫肠道(分别表示为Am CK和Am T)进行测序,通过相关生物信息学软件对DEmiRNAs进行预测和分析。利用TargetFinder软件预测DEmiRNAs的靶基因,然后利用Blast软件对靶基因进行GO和KEGG数据库的功能注释。通过Cytoscape软件构建DEmiRNAs与其靶m RNAs的调控网络。通过茎环实时荧光定量PCR(stem-loop RT-qPCR)验证测序数据的可靠性。【结果】Am CK和Am T的测序分别得到9 230 496和10 823 667条有效序列标签; Am CK vs Am T比较组中包含15个上调和6个下调mi RNAs,分别结合3 503和3 252个靶基因,它们可分别注释到40和39个GO terms以及104和99条代谢通路;进一步分析发现调控网络中的17个DEmiRNAs靶向结合116个与丝氨酸蛋白酶相关的m RNAs,14个DEmiRNAs靶向结合54个与泛素介导的蛋白水解相关的m RNAs。Stem-loop RT-qPCR验证结果显示随机选择的4个DEmiRNAs (mi R-251-x,mi R-9277-y,mi R-1672-x和mi R-4968-y)的表达量变化趋势与测序结果一致,表明测序数据真实可信。【结论】本研究率先对意蜂幼虫肠道在球囊菌胁迫后期的DEmiRNAs及其靶基因进行预测与分析,提供了mi RNAs的表达谱和差异表达信息。ame-miR-927b,mi R-429-y和mi R-8440-y等DEmiRNAs可能参与对丝氨酸蛋白酶的调控和对泛素介导的蛋白水解的调控,DEmiRNAs与靶基因之间存在复杂的调控网络关系。DEmiRNAs可参与到意蜂幼虫肠道与球囊菌间的互作。     

植物逆境胁迫相关miRNA研究进展

MicroRNAs(mi RNAs)是一类内源性小分子的非编码RNA,它通过对其靶基因mRNA的降解或抑制翻译来调控基因表达,进而参与调控植物相关生理活动。在逆境胁迫下,植物中的一些miRNA通过迅速表达并作用于某些与逆境相关的基因,以启动植物的某些抗逆信号系统,进而提高植物对不良环境的适应能力。就miRNA的产生、作用方式、研究方法及其在植物在逆境胁迫中的抗逆作用机制研究进行了综述,并对植物miRNA的研究发展趋势进行了展望。     

水稻(Oryza satica L.)干旱胁迫响应转录因子研究进展

干旱胁迫是水稻生长发育和产量的重要限制因子。转录因子在水稻对干旱胁迫响应中起关键调控作用。水稻中参与干旱胁迫的转录因主要有DREB转录因子、NAC转录因子、b ZIP转录因子、锌指蛋白转录因子、MYB转录因子、WRKY转录因子和TIFY转录因子等。这些转录因子与特异的靶基因的顺式作用元件结合调控水稻抗旱相关基因的表达,增强水稻对干旱胁迫的适应能力,本综述对这些转录因子在干旱胁迫中的表达调控和功能进行简要概述。     

靶向Wnt1的miRNA与circRNA及其靶基因间相互作用的生物信息学分析

为对靶向Wnt1的7种mi RNAs进行circ RNAs及其靶基因的预测,同时分析其与circ RNAs及靶基因间的相互作用,分别采用Starbase及mi RWALK软件,对文献报道的靶向Wnt1基因的let-7e、mi R-21、mi R-34a、mi R-122、mi R-148a、mi R-148b与mi R-152等7种mi RNAs的circ RNAs和对应的靶基因进行生物信息学预测.利用Cytoscape 3.2.1对这7种mi RNAs和预测所得到的circ RNAs及对应的靶基因进行网络分析.并进一步对预测到的靶基因通过DAVID软件进行通路分析.Starbase软件对这7种不同mi RNAs所预测的靶circ RNAs的数量分别为58、15、41、20、28、28、28个.分别比较mi RWALK中7~9个以上软件共有的mi RNAs及其与靶基因的关系,发现CHD7基因是唯一一个在三种不同预测范围内与mi R-21、mi R-148a、mi R-148b和mi R-152等4种mi RNAs相对应的靶基因.CNOT6、NBEA、ZFYVE26与ZDHHC17是在两种不同预测范围内与至少4个mi RNAs相对应的靶基因.在7种mi RNAs所预测靶基因相关的KEGG信号通路中,7~9个软件以上共有的信号通路为Focal adhesion信号通路、MAPK信号通路、Notch信号通路与TGF-beta信号通路.在MAPK信号通路中DUSP1与MRPS35_hsa_circ_001042均分别是与mi R-21、mi R-148a、mi R-148b及mi R-152等4种mi RNAs相互作用的靶基因与circ RNA.本研究对靶向Wnt1的mi RNAs及其相互作用的circ RNAs、靶基因与信号通路等进行了网络分析与预测,为进一步分析它们之间的相互作用奠定了基础.     

花生响应干旱胁迫的FERONIA类受体蛋白激酶基因克隆与表达分析

FERONIA(FER)类受体蛋白激酶是CrRLK1L(Catharanthus roseus RLK1-like)激酶亚家族成员,在植物受精、细胞伸长、顶端生长以及非生物胁迫响应等方面起重要作用。本研究克隆了两个花生(Arachis hypogaea)FER类受体蛋白激酶基因AhFER1和AhFER2,它们的完整编码序列(CDS)和相应基因组DNA序列完全一致,说明AhFER1和AhFER2基因编码区均无内含子,分别包括2 655和2 640 bp的完整开放阅读框,编码的蛋白分别含885和880个氨基酸,分子量分别为99.58和98.96 kDa,等电点分别为6.5和6.22。生物信息学分析发现,AhFER1及AhFER2的氨基酸序列与其他植物FER蛋白均具有较高同源性,都包含malectin-like和蛋白激酶催化域两个保守结构域。AhFER1和AhFER2基因在花生幼苗的叶、茎和根中的表达水平有差异:AhFER1基因在叶中表达量最高,其次是根,茎中表达量最低;而AhFER2基因则在茎中表达量最高,其次是叶,表达量最低是根。干旱胁迫对花生茎和根中AhFER1基因的表达以及花生叶、茎和根中AhFER2基因的表达均无影响,但干旱胁迫显著增强花生叶中AhFER1基因的表达,说明AhFER1基因可能在花生叶响应干旱胁迫时起重要作用。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.