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1.
Epigenetic reprogramming in mammalian development 总被引：1，自引：0，他引：1
DNA methylation is a major epigenetic modification of the genome that regulates crucial aspects of its function. Genomic methylation patterns in somatic differentiated cells are generally stable and heritable. However, in mammals there are at least two developmental periods-in germ cells and in preimplantation embryos-in which methylation patterns are reprogrammed genome wide, generating cells with a broad developmental potential. Epigenetic reprogramming in germ cells is critical for imprinting; reprogramming in early embryos also affects imprinting. Reprogramming is likely to have a crucial role in establishing nuclear totipotency in normal development and in cloned animals, and in the erasure of acquired epigenetic information. A role of reprogramming in stem cell differentiation is also envisaged. DNA methylation is one of the best-studied epigenetic modifications of DNA in all unicellular and multicellular organisms. In mammals and other vertebrates, methylation occurs predominantly at the symmetrical dinucleotide CpG (1-4). Symmetrical methylation and the discovery of a DNA methyltransferase that prefers a hemimethylated substrate, Dnmt1 (4), suggested a mechanism by which specific patterns of methylation in the genome could be maintained. Patterns imposed on the genome at defined developmental time points in precursor cells could be maintained by Dnmt1, and would lead to predetermined programs of gene expression during development in descendants of the precursor cells (5, 6). This provided a means to explain how patterns of differentiation could be maintained by populations of cells. In addition, specific demethylation events in differentiated tissues could then lead to further changes in gene expression as needed. Neat and convincing as this model is, it is still largely unsubstantiated. While effects of methylation on expression of specific genes, particularly imprinted ones (7) and some retrotransposons (8), have been demonstrated in vivo, it is still unclear whether or not methylation is involved in the control of gene expression during normal development (9-13). Although enzymes have been identified that can methylate DNA de novo (Dnmt3a and Dnmt3b) (14), it is unknown how specific patterns of methylation are established in the genome. Mechanisms for active demethylation have been suggested, but no enzymes have been identified that carry out this function in vivo (15-17). Genomewide alterations in methylation-brought about, for example, by knockouts of the methylase genes-result in embryo lethality or developmental defects, but the basis for abnormal development still remains to be discovered (7, 14). What is clear, however, is that in mammals there are developmental periods of genomewide reprogramming of methylation patterns in vivo. Typically, a substantial part of the genome is demethylated, and after some time remethylated, in a cell- or tissue-specific pattern. The developmental dynamics of these reprogramming events, as well as some of the enzymatic mechanisms involved and the biological purposes, are beginning to be understood. Here we look at what is known about reprogramming in mammals and discuss how it might relate to developmental potency and imprinting. 相似文献
2.
蜂王浆对雌性蜜蜂幼虫dynactin p62甲基化影响 总被引：1，自引：1，他引：0
【目的】研究蜂王浆对雌性蜜蜂幼虫dynactin p62甲基化水平影响。【方法】以意大利蜜蜂（Apis mellifera ligustica）和中华蜜蜂（A. cerana cerana）1日龄幼虫为试验材料,分别饲喂意大利蜜蜂蜂王浆和中华蜜蜂蜂王浆,并提取每组3日龄和6日龄幼虫样品的基因组DNA,利用Sequenom MassARRAY技术检测dynactin p62甲基化水平。【结果】饲喂异种蜂王浆可以更显著降低雌性蜜蜂幼虫dynactin p62整体甲基化水平;饲喂同一种蜂王浆,均为6日龄幼虫dynactin p62整体甲基化水平显著低于3日龄;2种蜂王浆对雌性蜜蜂幼虫dynactin p62各位点甲基化水平影响不同。【结论】2种蜂王浆对雌性蜜蜂幼虫dynactin p62整体甲基化水平和各位点甲基化水平影响不同,这说明不同蜂王浆具有不同的生物学效应。 相似文献
3.
【目的】研究意大利蜜蜂(Apis mellifera ligustica)蜂王与工蜂幼虫甲基供体S-腺苷甲硫氨酸(S-adenosylmethionine,SAM)合成与代谢的差异,为探索DNA甲基化与蜜蜂级型分化的关系提供理论依据。【方法】试验选用890只1日龄雌性蜂幼虫,分别来自5群姐妹蜂王群。其中445只进行人工育王(89只/群);剩余445只培育成工蜂(89只/群)。取3、4、5日龄蜂王和工蜂幼虫,测定其体内SAM合成与代谢关键酶基因表达和酶活性的差异。【结果】蜂王幼虫SAM含量随日龄的增加变化不显著(P0.05);工蜂幼虫SAM含量随日龄增加呈上升趋势(P0.05)。蜂王幼虫SAMS基因表达量随日龄增加呈梯度下降的趋势(P0.01),而工蜂幼虫SAMS表达随日龄变化不显著(P0.05);3日龄与4日龄时,蜂王幼虫SAMS表达量显著高于工蜂(P0.05),5日龄时,工蜂幼虫SAMS表达量显著高于蜂王(P0.05)。Dnmt1a与Dnmt3表达在两级型间差异不显著(P0.05),其中蜂王幼虫Dnmt1a表达随日龄增加无显著变化(P0.05),但其酶活性呈下降趋势(P0.05);工蜂幼虫Dnmt1a表达随日龄增加呈下降趋势(P0.05),其酶活性呈上升趋势(P0.01),其中3日龄与4日龄时,蜂王幼虫Dnmt1酶活性显著高于工蜂幼虫(P0.05),而5日龄时,工蜂幼虫Dnmt1酶活性显著高于蜂王幼虫(P0.05)。蜂王Dnmt3表达量随日龄增加呈下降趋势(P0.05),工蜂幼虫Dnmt3表达随日龄增加变化不显著(P0.05);蜂王幼虫Dnmt3酶活性随日龄变化不显著(P0.05),工蜂幼虫Dnmt3酶活性随日龄变化显著(P0.05),但蜂王幼虫Dnmt3酶活性在3、4、5日龄均显著高于工蜂幼虫(P0.01)。【结论】3—5日龄意大利蜜蜂蜂王幼虫与工蜂幼虫体内活性甲基供体SAM的合成与代谢存在差异。在4日龄之前,蜂王幼虫SAM的合成比工蜂活跃,4日龄之后,工蜂幼虫的SAM合成与蜂王幼虫相近;在4日龄之前,SAM参与DNA维持甲基化的代谢过程,蜂王幼虫比工蜂活跃,4日龄之后,工蜂幼虫比蜂王幼虫活跃;在3—5日龄,SAM参与DNA从头甲基化的代谢活性,蜂王幼虫始终不低于工蜂幼虫。 相似文献
4.
蜜蜂（Apis mellifera L.）幼虫级型分化差异蛋白质组分析 总被引：3，自引：1，他引：2
【目的】对蜜蜂（Apis mellifera L.）蜂王与工蜂级型分化期的蛋白质组进行比较,以探明蜂王和工蜂在级型分化时期蛋白质表达调控方面的异同。【方法】采用双向电泳建立蜂王和工蜂级型分化期蛋白质组表达 谱,获得图谱中蛋白质表达的数量、表达量、等电点和分子量等信息,然后进行比较蛋白质组研究。【结果】在幼虫3日龄,蜂王表达288个蛋白质,工蜂表达259个蛋白质,2种级型蜂共有蛋白质为156个,其中25个蛋白质在蜂王中的表达量显著大于（P＜0.05）工蜂,34个蛋白质工蜂表达量显著大于（P＜0.05）蜂王,而蜂王和工蜂的特异蛋白质分别为132个和103个;到幼虫5日龄时,蜂王表达274个蛋白质,工蜂为236个,这2种级型蜂共有蛋白质点为95个,其中蜂王15个蛋白质的表达量显著大于（P＜0.05）工蜂,工蜂26个蛋白质的表达量显著大于（P＜0.05）蜂王,而蜂王特异蛋白质点为179个,工蜂特异蛋白质点为141个;到蛹11日龄时,蜂王蛋白质组有311个蛋白质点,而工蜂则有278个蛋白质点,2种蜂共有蛋白质点为194个,其中蜂王45个蛋白质的表达量显著大于（P＜0.05）工蜂,工蜂35个蛋白质的表达量显著大于（P＜0.05）蜂王,而蜂王的特异蛋白质点为117个,工蜂特异蛋白质点为84个。【结论】在蜜蜂3日龄、5日龄、11日龄时,蜂王和工蜂的蛋白质表达谱存在显著差异,蜂王表达的蛋白质总数和特有蛋白质数都较工蜂多,说明蜂王幼虫的基因表达和代谢比工蜂幼虫更加旺盛。2种级型蜂发育中所表达的共有蛋白质可能是它们发育所必须的管家蛋白质,但级型间部分共有蛋白质的表达模式存在较大差异,在3个日龄中蜂王和工蜂中所表达的特异蛋白质表明在级型分化中,不同级型需要不同的蛋白质来调节各自的发育。这些特异蛋白质是否是级型发育相关的功能蛋白质,还有待进一步的研究。 相似文献
5.
蜂王浆介导外源基因转移的初步研究 总被引：1，自引：0，他引：1
采用DNA延滞实验研究蜂王浆与DNA的结合能力,然后通过蜂群哺育和人工培育两种方式,对1日龄工蜂幼虫进行短期饲喂,初步研究蜂王浆介导绿色荧光蛋白基因的方法和转移情况.结果表明:在蜂群环境下,蜂王浆中的外源DNA短期内不会完全被分解;但用蜂王浆作媒介并未实现蜜蜂基因转染,蜜蜂能否通过蜂王浆介导实现基因转移,还需进一步探讨. 相似文献
6.
Induction of tumors in mice by genomic hypomethylation 总被引：1，自引：0，他引：1
Gaudet F Hodgson JG Eden A Jackson-Grusby L Dausman J Gray JW Leonhardt H Jaenisch R 《Science (New York, N.Y.)》2003,300(5618):489-492
Genome-wide DNA hypomethylation occurs in many human cancers, but whether this epigenetic change is a cause or consequence of tumorigenesis has been unclear. To explore this phenomenon, we generated mice carrying a hypomorphic DNA methyltransferase 1 (Dnmt1) allele, which reduces Dnmt1 expression to 10% of wild-type levels and results in substantial genome-wide hypomethylation in all tissues. The mutant mice were runted at birth, and at 4 to 8 months of age they developed aggressive T cell lymphomas that displayed a high frequency of chromosome 15 trisomy. These results indicate that DNA hypomethylation plays a causal role in tumor formation, possibly by promoting chromosomal instability. 相似文献
7.
8.
【目的】通过对王浆高产蜜蜂（Apis mellifera L.）（浙江浆蜂）哺育蜂（6-12 d）咽下腺的磷酸化蛋白质组分析,以期探明蛋白质磷酸化修饰对王浆分泌的生物学意义。【方法】将哺育蜂咽下腺蛋白质液内酶切后,用固相金属离子亲和层析色谱法（IMAC）、强阳离子交换（SCX）及LC-MS/MS和生物信息学分析,对工蜂咽下腺磷酸化蛋白质组进行研究。【结果】在哺育蜂的咽下腺中,共鉴定117个蛋白质,其中6个蛋白质的6条磷酸肽段的8个位点发生磷酸化修饰。这些磷酸化蛋白质是王浆主蛋白1和7的前体、与蛋白翻译合成相关的60S酸性核糖体蛋白P0、P1、P2和60S核糖体蛋白L15。【结论】哺育蜂咽下腺核糖体蛋白发生的磷酸化修饰主要为促进王浆蛋白的高效合成,而磷酸化的王浆蛋白1和7可保证浆蜂在王浆高产的前提下仍保证其王浆具合理的钙磷比,提高营养价值,以满足蜂王产卵和幼虫发育的营养需求。研究结果在蛋白质磷酸化水平上为揭示浆蜂王浆的高产机理奠定了新的理论基础。 相似文献
9.
王浆蛋白是蜂王浆生物功能的物质基础,是由王浆蛋白基因家族(mrjps)编码合成的。但部分家族成员如MRJP7在王浆中的含量极少甚至检测不到。基因功能与其在生物体内的时空表达特性相关,为探究蜂王浆中含量较少的王浆主蛋白基因mrjp7在蜜蜂体内的表达和生物学功能,本研究利用荧光定量PCR技术对mrjp7在不同发育时期的工蜂和、成年工蜂、雄蜂和蜂王的不同发育时期和不同组织部位的表达进行定量分析检测。结果显示mrjp7在成年雄蜂体内的表达水平最低,成年蜂王次之,且在这两种蜜蜂类型它们的各不同发育时期和不同组织部位之间的表达量差异较小,其表达基本没有时空特异性。该基因在工蜂幼虫和蛹期的表达量同样较低且没有组织特异性,但在羽化后9日龄前后的哺育蜂王浆腺和头部脑组织内特异性高表达,其表达与工蜂的发育时期和组织密切相关。mrjp7在这与哺育蜂分泌蜂王浆王浆腺中的特异性高表达与哺育蜂所担负的哺育幼虫和蜂王的功能是相适应的,该结果在转录水平上证实了mrjp7该基因的的营养功能,为进一步的研究和应用打下了理论基础。。其在生殖和非生殖蜜蜂体内的差异表达可能与蜜蜂的生殖调控有关。 相似文献
10.
王浆高产蜜蜂（Apis mellifera L.）工蜂幼虫发育期蛋白质组分析 总被引：1，自引：1，他引：0
【目的】20世纪90年代中国成功培育出的王浆高产蜜蜂（Apis mellifera L.）是当今世界最优良的蜂种,使中国的王浆年产量高达2 600多吨,占世界总产量的90%以上,稳居世界第一,通过对该蜂种不同发育日龄工蜂幼虫的蛋白质组进行研究,以探明其发育机理。【方法】采用双向电泳法对王浆高产蜜蜂（Apis mellifera L.）不同发育期的工蜂幼虫进行蛋白质组研究。【结果】在幼虫期6 d的发育过程中,2日龄、4日龄、6日龄幼虫中分别检测到了262、418、194个蛋白点。这些蛋白的分子量在12.2～88.2 kD的较大范围之间,等电点在pH 4.00～9.24之间。有84个蛋白在幼虫期整个发育过程中均有表达,其中33%呈上调趋势,21%呈下调趋势,46%蛋白的表达没有规律。2日龄、4日龄、6日龄幼虫中分别有88、209、63个特异表达的蛋白。除此之外,有84个蛋白在幼虫发育的6日龄表达关闭,而在2日龄和4日龄幼虫中表达;有41个蛋白在2日龄表达关闭,而在4日龄和6日龄中表达;仅有6个蛋白在4龄日表达关闭,而在2日龄和6日龄表达。【结论】幼虫的发育过程有大量基因参与表达和调控,是一个复杂而动态有序的过程,且发育到4日龄的幼虫蛋白表达最为活跃。幼虫整个发育过程中的共有蛋白是发育必需的保守蛋白。幼虫不同的发育阶段由不同的特异蛋白进行调控。 相似文献
11.
This study is to compare the protein composition of the high royal jelly producing bee (A. m. ligustica) with that of Carniolian bee (A. m. carnica) during their worker larval developmental stage. The experiment was carried out by two-dimensional gel electrophoresis. The results showed that significant higher numbers of total proteins (283) were detected in larvae of high royal jelly producing bees (Jelly bee) than those of Camiolian bees (152) on 2-d-old larvae. Among them, 110 proteins were presented on both strains of bee larvae, whereas 173 proteins were specific to larvae of Jelly bees, and 42 proteins were exclusive to Carniolian larvae. However, on the 4th d, a significant higher number of total proteins (290) were detected in larvae of Jelly bees than those of Camiolian bees (240), 163 proteins resolved to both bee larvae, and 127 proteins were specific to Jelly bees and 77 proteins to Camiolian bees. Until the 6th d, also a significant higher number of total proteins (236) were detected in larvae of Jelly bees than those of Carniolian bees (180), 132 proteins were constantly expressed in two bee larvae, whereas 104 and 48 proteins are unique to Jelly bee and Camiolian bee larvae, respectively. We tentatively concluded that the metabolic rate and gene expression of Jelly bees larvae is higher than those of Carniolian bees based proteins detected as total proteins and proteins specific to each stage of two strains of bee larvae. Proteins constantly expressed on 3 stages of larval development with some significant differences between two bee strains, and proteins unique to each stage expressed differences in term of quality and quantity, indicating that larval development needed house keeping and specific proteins to regulate its growth at different development phage, but the expression mold is different between two strains of larval development. 相似文献
12.
【目的】比较王浆高产蜜蜂（Apis mellifera L.浆蜂）与原种意大利蜜蜂（Apis mellifera L.原种意大利蜜蜂）工蜂卵期3 d发育阶段蛋白质组。【方法】采用双向电泳的方法比较两个蜂种卵期发育蛋白质组。【结果】结果显示，两个蜂种卵期3 d所得6张胶图检测到的蛋白点均具有相同的分子量与等电点范围，分子量范围为11.00～94.00 kD，等电点范围为3.40～8.60。在工蜂卵3 d的发育过程中，浆蜂分别检测到502、523和516个蛋白点，而原种意大利蜜蜂分别检测到349、361和354个蛋白点。同时，卵期3天发育过程中，两个蜂种分别检测到180、151和197个共有的表达蛋白。此外，浆蜂还检测到322、372和319个特有蛋白，而原种意大利蜜蜂也分别检测到169、210、157个特有蛋白，这些蛋白90%以上都是低表达量蛋白。【结论】在工蜂胚胎发育过程中，浆蜂有更多的基因参与表达调控，特有蛋白可能与调节王浆产量相关的基因相关。 相似文献
13.
This study is to compare the protein composition of the high royal jelly producing bee （A. m. ligustica） with that of Carniolian bee （A. m. carnica） during their worker larval developmental stage. The experiment was carried out by two- dimensional gel electrophoresis. The results showed that significant higher numbers of total proteins （283） were detected in larvae of high royal jelly producing bees （Jelly bee） than those of Carniolian bees （152） on 2-d-old larvae. Among them, 110 proteins were presented on both strains of bee larvae, whereas 173 proteins were specific to larvae of Jelly bees, and 42 proteins were exclusive to Carniolian larvae. However, on the 4th d, a significant higher number of total proteins （290） were detected in larvae of Jelly bees than those of Carniolian bees （240）, 163 proteins resolved to both bee larvae, and 127 proteins were specific to Jelly bees and 77 proteins to Camiolian bees. Until the 6th d, also a significant higher number of total proteins （236） were detected in larvae of Jelly bees than those of Carniolian bees （180）, 132 proteins were constantly expressed in two bee larvae, whereas 104 and 48 proteins are unique to Jelly bee and Carniolian bee larvae, respectively. We tentatively concluded that the metabolic rate and gene expression of Jelly bees larvae is higher than those of Carniolian bees based proteins detected as total proteins and proteins specific to each stage of two strains of bee larvae. Proteins constantly expressed on 3 stages of larval development with some significant differences between two bee strains, and proteins unique to each stage expressed differences in term of quality and quantity, indicating that larval development needed house keeping and specific proteins to regulate its growth at different development phage, but the expression mold is different between two strains of larval development. 相似文献
14.
保幼激素类似物ZR-512对蜜蜂蜂王发育、交配和蜂群繁殖的影响 总被引：3，自引：1，他引：3
在蜜蜂人工育王过程中 ,用保幼激素类似物 ZR-5 1 2滴注于王台内的蜂王浆中 ,研究其对蜜蜂蜂王发育、交配、产卵和蜜蜂群势增长等影响 .结果表明 ,卵孵化后 (84± 2 ) h蜂王幼虫用保幼激素类似物 ZR-5 1 2处理 ,每只处理剂量为 0 .0 5、0 .0 0 5μg对蜂王体重调控效果最好 ;以保幼激素类似物 ZR-5 1 2处理蜂王 ,可使交配时间提前 2 .4-2 .6d;有效产卵量增加1 84.2 5 -1 93 .5粒·d- 1 ;蜜蜂群势比对照组平均增长 1 9.5 1 % . 相似文献
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【目的】研究中华蜜蜂（Apis cerana cerana）二倍体雄蜂并进行人工培育,测定其形态指标,明确中华蜜蜂二倍体雄蜂的生物学特性。【方法】采用复式移虫方法培育中华蜜蜂蜂王,待蜂王性成熟时进行CO2麻醉处理后放回原群,用糖水进行奖励饲喂。蜂王产下大量未受精卵,待雄蜂出房后采用颜料进行标记。雄蜂性成熟后,利用蜂王人工授精技术使蜂王与本群子代雄蜂进行母子回交（多雄交配）。控制蜂王产卵,将工蜂巢房中刚孵化的幼虫移至恒温恒湿培养箱（相对湿度：95%;温度：35℃）中进行人工培育。幼虫前3日龄食物配制为：蜂王浆90％,无菌水10％;第4-6日龄食物成分比例为：蜂王浆50％,葡萄糖6％,果糖6％,酵母抽出物1％,无菌水37％;从第7日龄起食物比例为：蜂王浆43％,葡萄糖9％,果糖9％,酵母抽出物1％,无菌水38％,直到幼虫进入排便期为止。采用流式细胞仪对人工培育和蜂群工蜂巢房出房的雄蜂进行倍性鉴定,并对蜂群工蜂巢房出房的单倍雄蜂和二倍体雄蜂进行形态指标测定比较。【结果】室内人工培育的中华蜜蜂总羽化率偏低,平均为36％,其中26.9％为雄蜂;通过流式细胞仪分析雄蜂倍性发现人工培育的雄蜂92％为二倍体,蜂群工蜂巢房中出房的雄蜂82%为二倍体雄蜂;形态指标测定显示,二倍体雄蜂的初生重与生殖器官重分别为99.78和6.05 mg,均比单倍体雄蜂（分别为105.64和7.02 mg）显著偏小,而前翅长、前翅宽、翅钩数等指标差异不显著。【结论】中华蜜蜂近亲交配的蜂群会产生二倍体雄蜂,部分二倍体雄蜂可在蜂群中发育至成蜂出房,其形态指标与单倍体雄蜂存在一定差异。 相似文献
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Functional CpG methylation system in a social insect 总被引：1，自引：0，他引：1
Wang Y Jorda M Jones PL Maleszka R Ling X Robertson HM Mizzen CA Peinado MA Robinson GE 《Science (New York, N.Y.)》2006,314(5799):645-647
DNA methylation systems are well characterized in vertebrates, but methylation in Drosophila melanogaster and other invertebrates remains controversial. Using the recently sequenced honey bee genome, we present a bioinformatic, molecular, and biochemical characterization of a functional DNA methylation system in an insect. We report on catalytically active orthologs of the vertebrate DNA methyltransferases Dnmt1 and Dnmt3a and b, two isoforms that contain a methyl-DNA binding domain, genomic 5-methyl-deoxycytosine, and CpG-methylated genes. The honey bee provides an opportunity to study the roles of methylation in social contexts. 相似文献
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将pGFP-2质粒线性化,利用精子介导,通过人工授精技术导入意大利蜜蜂处女王,然后将授精王介绍到无王群繁殖后代。结果:试验群产生了一群绿色荧光阳性蜜蜂;对阳性蜂群后代分析发现,1~2日龄幼虫能检测到荧光,提取蜜蜂DNA进行PCR扩增得到预想的片断,通过RT-PC分析,从转录水平上证实转导的外源基因获得表达。结论:以绿色荧光蛋白(GFP)基因为报告基因,通过精子介导法能够生产克隆转基因蜜蜂。 相似文献
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对单、复２种不同形式移虫育王的王台接受率和蜂王初生重进行了对比试验．试验结果显示：（１）单式移虫的王台接受率（５８．１１％）与复式移虫的王台接受率（６２．６７％）差异不显著（Ｐ＞０．０５）；（２）单式移虫育出的蜂王初生重（Ｘ＝２３５．９６ｍｇ）与复式移虫育出的蜂王初生重（Ｘ＝２４１．５７ｍｇ）差异不显著（Ｐ＞０．０５）．据此，我们认为培育蜂王应采用单式移虫以省工省时． 相似文献