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Establishment of cohesion between sister chromatids is coupled to replication fork passage through an unknown mechanism. Here we report that TRF4, an evolutionarily conserved gene necessary for chromosome segregation, encodes a DNA polymerase with beta-polymerase-like properties. A double mutant in the redundant homologs, TRF4 and TRF5, is unable to complete S phase, whereas a trf4 single mutant completes a presumably defective S phase that results in a failure of cohesion between the replicated sister chromatids. This suggests that TRFs are a key link in the coordination between DNA replication and sister chromatid cohesion. Trf4 and Trf5 represent the fourth class of essential nuclear DNA polymerases (designated DNA polymerase kappa) in Saccharomyces cerevisiae and probably in all eukaryotes.  相似文献   

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淮亚红  许尚忠 《安徽农业科学》2009,37(18):8385-8388
[目的]探讨牛Trf2基因的生物学功能,为进一步研究该基因对牛精液品质的影响奠定基础。[方法]以牛睾丸组织为材料,根据GenBank中发表的人Trf2基因序列,结合生物信息学技术,设计并合成3对引物,采用RT-PCR方法克隆牛Trf2cDNA,并运用DNA-MAN软件及在线工具对所得到的序列进行生物信息学分析。采用牛肾脏、肝脏、睾丸、肺、瘤胃、子宫、小肠、心脏、脾脏、卵巢和脂肪组织共11个组织,以牛β-actin基因为内参基因,对牛Trf2基因的组织表达谱进行分析。[结果]牛Trf2基因cDNA长度为1701bp(Gen-Bank登录号EU140625)。包含由561个碱基组成的开放读码框(ORF),该ORF包含1个UGA终止密码子,编码186个氨基酸;在进化关系上,牛首先和人、大鼠、狗聚成一类,然后与袋鼠聚成第1群,再与小鼠聚成第2群。Trf2蛋白舍有2个结构域TLF和SPT15。牛Trf2基因在各个组织中都有表达,在睾丸组织中表达最高。[结论]获得了牛Trf2基因的cDNA序列(GenBank登录号EU140625);牛Trf2蛋白可能对牛精液品质有影响。  相似文献   

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热应激对小鼠睾丸Hsp70-2基因mRNA转录水平的影响   总被引:1,自引:0,他引:1  
用半定量RT-PCR方法检测不同温度、相同时间(4 h)热应激处理小鼠睾丸组织中Hsp70-2基因的mRNA转录水平,以研究热应激对Hsp70-2基因mRNA转录的影响。结果显示,各热应激组小鼠睾丸Hsp70-2 mRNA转录水平下降,并且温度越高,其下降幅度越大。与对照组相比,33℃组小鼠Hsp70-2 mRNA相对转录水平显著(P<0.05)下降,而37℃组和42℃组下降极显著(P<0.01)。42℃组Hsp70-2 mRNA相对转录水平仅为对照组的44.7%。上述结果说明,热应激使Hsp70-2基因mRNA转录水平下降,热应激对雄性生殖机能的影响与Hsp70-2减少有关,而Hsp70-2 mRNA转录水平可以作为热应激对雄性生殖机能损伤程度的判断指标之一。  相似文献   

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构建了含拟南芥Ca2+泵基因ACA2特异片段反向重复结构的RNA i载体,通过根癌农杆菌介导转化拟南芥,用卡那霉素筛选和PCR检测,获得了12个T3代纯合体转基因株系;半定量RT-PCR方法检测ACA2在转基因株系中转录的结果表明,其转录产物比野生型(WT)明显降低,且转基因株系之间差异明显,表达水平有1个梯度关系,因此,我们初步确定沉默Ca2+泵基因ACA2的RNA i载体是起作用的。  相似文献   

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Mammalian telomeres are protected by a six-protein complex: shelterin. Shelterin contains two closely related proteins (TRF1 and TRF2), which recruit various proteins to telomeres. We dissect the interactions of TRF1 and TRF2 with their shared binding partner (TIN2) and other shelterin accessory factors. TRF1 recognizes TIN2 using a conserved molecular surface in its TRF homology (TRFH) domain. However, this same surface does not act as a TIN2 binding site in TRF2, and TIN2 binding to TRF2 is mediated by a region outside the TRFH domain. Instead, the TRFH docking site of TRF2 binds a shelterin accessory factor (Apollo), which does not interact with the TRFH domain of TRF1. Conversely, the TRFH domain of TRF1, but not of TRF2, interacts with another shelterin-associated factor: PinX1.  相似文献   

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Transcription of class III genes: formation of preinitiation complexes   总被引:125,自引:0,他引:125  
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Strand-specific postreplicative processing of mammalian telomeres   总被引:1,自引:0,他引:1  
Telomeres are specialized nucleoprotein structures that stabilize the ends of linear eukaryotic chromosomes. In mammalian cells, abrogation of telomeric repeat binding factor TRF2 or DNA-dependent protein kinase (DNA-PK) activity causes end-to-end chromosomal fusion, thus establishing an essential role for these proteins in telomere function. Here we show that TRF2-mediated end-capping occurs after telomere replication. The postreplicative requirement for TRF2 and DNA-PKcs, the catalytic subunit of DNA-PK, is confined to only half of the telomeres, namely, those that were produced by leading-strand DNA synthesis. These results demonstrate a crucial difference in postreplicative processing of telomeres that is linked to their mode of replication.  相似文献   

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Senescence induced by altered telomere state, not telomere loss   总被引:1,自引:0,他引:1  
Primary human cells in culture invariably stop dividing and enter a state of growth arrest called replicative senescence. This transition is induced by programmed telomere shortening, but the underlying mechanisms are unclear. Here, we report that overexpression of TRF2, a telomeric DNA binding protein, increased the rate of telomere shortening in primary cells without accelerating senescence. TRF2 reduced the senescence setpoint, defined as telomere length at senescence, from 7 to 4 kilobases. TRF2 protected critically short telomeres from fusion and repressed chromosome-end fusions in presenescent cultures, which explains the ability of TRF2 to delay senescence. Thus, replicative senescence is induced by a change in the protected status of shortened telomeres rather than by a complete loss of telomeric DNA.  相似文献   

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The gene encoding gD of isolate Luojing of infectious bovine rhinotracheitis virus (IBRV)was amplified,sequenced, and cloned into plasmid pcDNA3.1, resulting in a recombinant pcDNA-gD. Groups of BALB/c mice were injected with 100μg of plasmid only or together with liposome. After immunization, serum samples were collected from mice every 2 weeks for a 10-week period and tested for protein-specific antibody with enzyme-linked immunosorbent assay (ELISA). It was showed that the plasmid encoding IBRV glycopretein D developed gene-specific antibody. This report indicates the potential of DNA injection as a method of vaccination.  相似文献   

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梁平  宋洪元 《广西农业科学》2014,45(8):1375-1379
花青素是高等植物中发现的一种次生代谢物,能够决定花和果实的颜色,保护植物免受各种生物和非生物胁迫损伤。花青素生物合成由一系列结构基因编码的酶催化完成,属于类黄酮途径一个特异分支,其合成结构基因的表达受由MYB、bHLH和WD40 3类转录因子组成的MBW(MYB-bHLH-WD40)转录复合体协同调控。文章主要就MYB、bHLH和WD40 3类转录因子在调节结构基因表达和花青素合成中的功能和作用进行综述。  相似文献   

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