Differential control of U1 small nuclear RNA expression during mouse development

During normal mouse development the relative amounts of two types of U1 small nuclear RNA's (U1 RNA) change significantly. Fetal tissues have comparable levels of the two major types of mouse U1 RNA's, mU1a and mU1b, whereas most differentiated adult tissues contain only mU1a RNA's. Those adult tissues that also accumulate detectable amounts of embryonic (mU1b) RNA's (for example, testis, spleen, and thymus) contain a significant proportion of stem cells capable of further differentiation. Several strains of mice express minor sequence variants of U1 RNA's that are subject to the same developmental controls as the major types of adult and embryonic U1 RNA. The differential accumulation of embryonic U1 RNA's may influence the pattern of gene expression during early development and differentiation.     

PPAR基因进化及其在脊椎动物发育过程中的表达

过氧化物酶体增殖剂激活受体(Peroxisome proliferator activated receptor,PPAR)是核激素受体家族中的配体激活受体,在不同的物种中已经发现了它的3种亚型,即PPARα、PPARβ(也有称δ)和PPARγ。它们在多细胞动物进化的过程中获得配体结合能力,通过结合到相应的激活剂上,在一些重要的代谢途径中刺激靶基因的表达。其中PPARα和β在爪蟾的胚胎发育早期表达的组织范围较广,在后期表现出较大的组织特异性;在啮齿动物中PPARα、β和γ在胎儿发育和成年动物体内表现出特定的时间和组织上的依赖性的表达模式;PPARα和γ在人体内的表达范围较窄,而PPARβ则较广。     

Tissue-specific expression in transgenic mice of a fused gene containing RSV terminal sequences

Transgenic mice were generated with pRSV-CAT, a chimeric gene construct containing the long terminal repeat of Rous sarcoma virus (RSV) linked to the bacterial gene encoding chloramphenicol acetyltransferase (CAT). CAT expression, detected in adult animals of five independent strains, was preferentially directed to organs rich in tendon, bone, and muscle. This pattern reflects the disease specificity of the intact virus and suggests that the tissue tropism of RSV is determined at least in part by the presence of endogenous tissue-specific factors that can promote expression of genetic information linked to the long terminal repeat. In two of the mouse strains, insertion of the pRSV-CAT DNA resulted in developmental abnormalities. One of these strains was characterized by a dominant trait of embryonic lethality, the other by a recessive trait of fused toes in all four feet.     

Simultaneous expression of globin genes for embryonic and adult hemoglobins during mammalian ontogeny

The dominant hemoglobin of the adult hamster was detected in yolk-sac erythroid cells, and its identity was confirmed by peptide mapping and by analysis of relevant peptides. Both the presence and active synthesis of two embryonic hemoglobins presumed to exist only in yolk-sac erythroid cells were detected in neonatal liver and spleen. Thus the time span of expression of both embryonic and adult globin genes during mammalian ontogeny may be considerably broader than presently believed.     

万寿菊类胡萝卜素裂解双加氧酶基因CCD4b的克隆与表达分析

为探讨万寿菊类胡萝卜素降解过程中CCD4b的功能,以万寿菊(Tagetes erecta L.)‘Scarletade’品种舌状花为试材,利用同源基因克隆获得CCD4b,命名为TeCCD4b (GenBank:KY450708)。序列分析表明TeCCD4b cDNA全长为1 725bp,编码区长度1 392bp,所编码的产物含463个氨基酸,主要定位于质体膜,属RPE65超家族,包含CCD家族保守的结构域;同源分析表明TeCCD4b与向日葵HaCCD4-L、案头菊CmCCD4b同源性最高;系统进化树分析显示TeCCD4b与HaCCD4-L和CmCCD4b亲缘关系最近,与其他物种的CCD4和CCD4a存在差异,表明TeCCD4b在进化过程中保守性不强,不同种属之间具有明显差异,基本符合植物的进化规律;荧光定量PCR结果显示TeCCD4b在舌状花发育过程中均有表达,且与万寿菊花色变化基本一致,表明万寿菊舌状花颜色变化可能与TeCCD4b表达量高低相关。     

A single amino acid mutation contributes to adaptive beach mouse color pattern

Natural populations of beach mice exhibit a characteristic color pattern, relative to their mainland conspecifics, driven by natural selection for crypsis. We identified a derived, charge-changing amino acid mutation in the melanocortin-1 receptor (Mc1r) in beach mice, which decreases receptor function. In genetic crosses, allelic variation at Mc1r explains 9.8% to 36.4% of the variation in seven pigmentation traits determining color pattern. The derived Mc1r allele is present in Florida's Gulf Coast beach mice but not in Atlantic coast mice with similar light coloration, suggesting that different molecular mechanisms are responsible for convergent phenotypic evolution. Here, we link a single mutation in the coding region of a pigmentation gene to adaptive quantitative variation in the wild.     

利用肉色相关候选基因对肉色性状进行预测

1)选用肥育期苏太猪100头,屠宰后取背最长肌,采用相对定量RT-PCR法测定肉色候选基因肌红蛋白(MB)、肌细胞增强因子(MEF2)、钙调神经磷酸酶(Calcineurin)和活化T细胞核因子(NFATc1)mRNA水平;分别测定MB浓度和肌肉表观色度参数,并对肉色进行评分,再分析上述参数间的相关性.结果显示:MB mRNA与肉色评分(r=0426**(**:P＜001))、a*值(r=0379**)、MB浓度(r=0364**)均呈正相关;NFATc1 mRNA与肉色评分(r=0407**)、a*值(r=0406**)、MB浓度(r=0345*(*:P＜005))、MB mRNA(r=0571**)也均存在正相关;且肉色候选基因表达之间均呈正相关.2)选用生长速度慢的肉脂兼用型二花脸猪与生长速度快的瘦肉型大白猪,分别于3、20、45、90、120和180日龄采集背最长肌样品,用相对定量RT-PCR法分析背最长肌中肉色相关候选基因表达的发育性变化,并进行品种和性别间比较.结果显示:MB、MEF2、Calcineurin mRNA发育性变化在品种间二花脸猪高于大白猪;NFATc1 mRNA则相反,大白猪高于二花脸猪.两品种MB、NFATc1、Calcineurin mRNA均在20日龄急剧升高,MEF2在两品种间差异最大,除3日龄外,二花脸公猪均显著高于大白公猪.性别间二花脸公、母猪MB mRNA和MEF2 mRNA仅在发育后期180日龄有显著差异,Calcineurin mRNA和NFATc1 mRNA在整个发育阶段均无显著差异.结论:推定最佳早期选育时间点为20日龄.     

Living nautilus embryos: preliminary observations

Nautilus, long recognized as the most primitive living cephalopod, provides insight into molluscan evolution. Despite many attempts, embryos have not been observed until now. This report details the surface morphology and extraembryonic circulatory pattern. It was found that development, as in other extant cephalopods, is direct, without larval stages. There appears to be no embryonic protoconch associated with shell ontogeny.     

小鼠早期胚胎发育过程中母源基因降解相关内源性小干扰RNA筛选与鉴定

为探究endo-siRNA在小鼠胚胎母源基因降解过程中的功能,通过生物信息学分析对小鼠母源基因和对应小RNA作筛选与鉴定,研究发现近三分之二母源基因为小RNA靶标。母源基因在早期胚胎发育过程中表达模式分析表明endo-siRNA与母源基因表达呈较强负相关,预示endo-siRNA在母源基因降解过程中具有重要功能。验证表明, endo-siRNA可在转录后水平调控母源mRNA水平,调控母源基因降解。研究结果为哺乳动物母胚转换的相关研究提供理论基础。     

A -defensin mutation causes black coat color in domestic dogs

Genetic analysis of mammalian color variation has provided fundamental insight into human biology and disease. In most vertebrates, two key genes, Agouti and Melanocortin 1 receptor (Mc1r), encode a ligand-receptor system that controls pigment type-switching, but in domestic dogs, a third gene is implicated, the K locus, whose genetic characteristics predict a previously unrecognized component of the melanocortin pathway. We identify the K locus as beta-defensin 103 (CBD103) and show that its protein product binds with high affinity to the Mc1r and has a simple and strong effect on pigment type-switching in domestic dogs and transgenic mice. These results expand the functional role of beta-defensins, a protein family previously implicated in innate immunity, and identify an additional class of ligands for signaling through melanocortin receptors.     

荔枝果皮叶绿素、类胡萝卜素、花色苷的形成规律及对果色的影响

荔枝果色的形成是多种色素共同作用的结果,不同的荔枝品种果皮色素的变化规格各不相同,。妃子笑着色较差的一个重要原因是因其果皮叶绿素含量过高,妨碍了花色苷红色的表现,糯米糍果皮叶绿素的降解为红色的显现提供了有利条件。     

不同品种鸭胚胎期骨骼肌成肌细胞GHR和IGF 1 mRNA表达差异分析

为探讨生长激素受体（growth hormone receptor,GHR）和胰岛素样生长因子 1（Insulin like growth factor 1,IGF 1）在不同品种鸭胚胎期骨骼肌成肌细胞中的表达差异。选择生长速度不同的金定鸭和高邮鸭为试验动物,采用实时荧光定量PCR方法检测鸭13,15,17,19,21和23胚龄时胸肌和腿肌成肌细胞GHR,IGF 1 mRNA的表达情况,并进行了品种间比较。结果发现：13胚龄时,高邮鸭胸肌和腿肌成肌细胞IGF 1的表达均显著高于金定鸭（P<0.05）;17胚龄是两个品种鸭GHR和IGF 1共同的表达高峰期;17胚龄之后,鸭胸肌和腿肌成肌细胞GHR和IGF 1表达均显著降低。在19,21胚龄时,高邮鸭胸肌成肌细胞2个基因的表达均显著高于金定鸭（P<0.05）,而腿肌成肌细胞GHR和IGF 1表达在品种间无显著差异（P>0.05）。鸭胚胸肌和腿肌成肌细胞GHR和IGF 1表达呈现极显著的正线性相关（P<0.01）。提示：GHR和IGF 1的表达谱及各自在品种间的变化规律基本一致;鸭胚骨骼肌成肌细胞GHR和IGF 1 mRNA表达有组织特异性,二者之间可能存在正调控的作用机制。     

Age-dependent changes in proteins of Drosophila melanogaster

Several molecular theories of aging postulate that there are age-dependent changes in gene expression and that these changes contribute to the reduction in the viability of senescent cells. High-resolution, semiautomated, quantitative two-dimensional gel electrophoresis of many soluble proteins was used to test this hypothesis in Drosophila. Two-dimensional protein gel patterns were analyzed for each of three age groups of [(35)S]methionine-labeled adult male Drosophila melanogaster, which, except for their spermatocytes, consist entirely of fixed postmitotic cells. Seven relatively abundant polypeptides expressed in middle-aged (28-day-old) flies were absent in both young(10-day-old) and old (44-day-old) flies. Quantitative analyses of an additional 100 polypeptides were carried out by computer-assisted microdensitometry of fluorograms of the gel preparations. These analyses revealed a significant age-related heterogeneity in the quantitative distribution of radiolabel in these proteins. The data indicate that the qualitative pattern of gene expression is identical in young and old flies, but that profound quantitative changes occur in the expression of proteins during the Drosophila life-span.     

葡萄风信子黄酮醇合酶基因克隆和表达分析

以葡萄风信子‘亚美尼亚’的根、茎、叶、花为材料,采用RT-PCR技术克隆得到一条FLS基因,命名为MaFLS2。生物信息学分析表明,该基因cDNA全长为1 152 bp,含有完整的开放读码框1 056 bp,编码353个氨基酸,MaFLS2蛋白是一种亲水性蛋白,氨基酸序列含有典型的DIOX_N结构域(2-酮戊二酸-双加氧酶活性的N端区域)和2OG-FeII_Oxy超家族结构域,属于2-酮戊二酸-双加氧酶(2-ODDs)蛋白家族。实时定量PCR结果显示,MaFLS2基因在蓝白葡萄风信子中的表达存在组织特异性,蓝色品种‘亚美尼亚’中在花蕾未着色时表达量最高,而白色品种‘白丽人’在根中表达量最高, 在花发育的不同阶段,MaFLS2基因在‘亚美尼亚’中的表达峰值出现在花蕾未着色时期,基因表达总体呈现出先降低后升高再降低的趋势,而在‘白丽人’中的表达峰值出现在转色中期,总体呈现出先升后降的趋势。研究结果为开展单子叶植物花色育种提供了理论依据。     

Plant embryogenesis: zygote to seed

Most differentiation events in higher plants occur continuously in the postembryonic adult phase of the life cycle. Embryogenesis in plants, therefore, is concerned primarily with establishing the basic shoot-root body pattern of the plant and accumulating food reserves that will be used by the germinating seedling after a period of embryonic dormancy within the seed. Recent genetics studies in Arabidopsis have identified genes that provide new insight into how embryos form during plant development. These studies, and others using molecular approaches, are beginning to reveal the underlying processes that control plant embryogenesis.     

鸡生长发育早期骨骼肌IGF1R mRNA表达规律研究

以生长速度不同的花山麻鸡和清远麻鸡为试验素材,采用实时荧光定量PCR方法检测鸡9、12、16、21胚龄(E9 d、E12 d、E16 d、E21 d)和出雏后7日龄(7 d)时胸肌和腿肌中IGF1R mRNA表达变化情况,并与肌肉质量进行相关性研究。结果发现,21胚龄时,花山麻鸡和清远麻鸡胸肌质量都出现了显著降低,腿肌质量持续增长。花山麻鸡胸肌IGF1R mRNA表达呈前高后低趋势,9胚龄时表达量最高,之后显著降低并维持在较低的水平,出雏后7日龄时表达量再次下降;清远麻鸡在胸肌中的表达则呈“波浪形”,9胚龄和16胚龄表达量升高,其他日龄表达量显著降低。腿肌中,花山麻鸡IGF1R mRNA表达量在16胚龄之后显著降低;清远麻鸡腿肌IGF1R mRNA表达呈依次递减模式,各时间点之间差异显著(P<0.05)。品种间各个时间点胸肌和腿肌IGF1R mRNA表达量均呈显著差异(P<0.05)。两个品种骨骼肌IGF1R mRNA表达与胸肌、腿肌质量均呈极显著相关(P<0.01)。以上结果初步揭示了生长发育早期不同品种鸡胸肌和腿肌IGF1R基因表达发育变化趋势和品种差异,为深入研究IGF1R基因在鸡肌肉发育中的调控机理提供基础资料。     

Requirement of the RNA editing deaminase ADAR1 gene for embryonic erythropoiesis

The members of the ADAR (adenosine deaminase acting on RNA) gene family are involved in site-selective RNA editing that changes adenosine residues of target substrate RNAs to inosine. Analysis of staged chimeric mouse embryos with a high contribution from embryonic stem cells with a functional null allele for ADAR1 revealed a heterozygous embryonic-lethal phenotype. Most ADAR1+/- chimeric embryos died before embryonic day 14 with defects in the hematopoietic system. Our results suggest the importance of regulated levels of ADAR1 expression, which is critical for embryonic erythropoiesis in the liver.     

斑马鱼中snrpc基因的发育时序表达分析

为了深入研究鱼类snrpc基因的作用机制,通过分析斑马鱼snrpc的发育时序表达,来探讨snrpc基因在斑马鱼中的功能机理。从斑马鱼的胚胎中提取RNA,进行反转录、PCR、克隆等,得到snrpc基因在胚胎发育不同时期的表达水平。结果表明,在斑马鱼胚胎发育初期,snrpc表达量较高,随着胚胎的不断发育,snrpc的m RNA表达量有所下降,到后期表达量又上升。因此,snrpc表达量的变化可能预示着snrpc发挥功能的关键时期,对snrpc的克隆和表达分析,为后续进一步研究其相关功能奠定了基础。