The synergetic effects of two CCAAT boxes in Aspergillus niger glaA gene promoter on activation of PglaA transcription

EMSA and footprinting analyses have revealed that the -489—-414 bp and the -390—-345 bp (designated DC and PC respectively) upstream of the Aspergillus niger T21 glaA gene were bound by one protein factor in the A. niger T21 whole cell extract. Both DC and PC contained CCAAT pentanucleotides. The functions of DC and PC in regulation of expression of glucoamylase (GLA) were studied. CCAAT pentanucleotides were replaced with CGTAA and the mutated DNA fragments DCm and PCm lost the binding activities of protein factors in vitro. In vivo when either DC or PC was mutated or the relative orientations between them were changed on the PglaA, the transcriptional activity of PglaA decreased to a basal level. Introduction of multi-copies of DC into the original site at the PglaA in A. niger T21 decreased the expression of endogenous GLA expression and the exogenous reporter E. coli uidA gene introduced under the PglaA promoter, while having no effect on the uidA gene under the control of PgpdA. EMSA re-vealed that the levels of the specific DNA-binding protein factors in the transformants maintained the same meaning that introduction of multi-copies of DC caused the titration effect. AnghapC gene was cloned from A. niger T21 cDNA and introduced into the DC multi-copied strains. The expression of AnghapC improved the expression of the endogenous GLA and the exogenous gene controlled by PglaA. These results showed that both the CCAAT pentanucleotides were necessary for DC and PC binding to the protein factors, and the simultaneous binding of DC and PC to the protein was necessary for promoting the transcriptional activity of PglaA. AngHapC was the specific positive trans-acting protein factor binding to DC.

Functions of nuclear factor Y in nervous system development,function and health

Nuclear factor Y is a ubiquitous heterotrimeric transcription factor complex conserved across eukaryotes that binds to CCAAT boxes,one of the most common motifs found in gene promoters and enhancers.Over the last 30 years,research has revealed that the nuclear factor Y complex controls many aspects of brain development,including differentiation,axon guidance,homeostasis,disease,and most recently regeneration.However,a complete understanding of transcriptional regulatory networks,including how the nuclear factor Y complex binds to specific CCAAT boxes to perform its function remains elusive.In this review,we explore the nuclear factor Y complex’s role and mode of action during brain development,as well as how genomic technologies may expand understanding of this key regulator of gene expression.

核因子Y在植物中的分类及其功能概述

核因子Y(NF-Y)是近十年来新发现的具有多种生物功能的植物特异转录因子,由三个不同的亚基组成,分别是NF-YA(CBF-B/)HAP、NF-YB(CBF-A/HAP3)和NF-YC(CBF-C/HAP5)。NF-Y是一种典型的通过与调控因子相互作用来调控下游基因表达的转录因子,通过保守专一性的序列与真核生物启动子区域的CCAAT框相结合。NF-Y在植物中普遍存在,并参与调节植物体的诸多重要生理过程,包括逆境反应,胚胎和叶绿体发育,光合作用等重要生理过程。文章主要就植物NF-Y转录因子的基本结构特征、生物学功能、研究方法及进展等进行了综述。

病毒基因组启动子识别的人工神经网络方法

本文运用神经网络方法，并结合病毒基因分子生物学有关理论与统计事实，对病毒基因启动子区域进行了识别，文中选择了共35个基因组，作为研究对象．学习组选择了28个基因组，预测组选择了7个基因组，结果表明，将神经网络模型与病毒基因有关理论相结合，能够运用计算方法，以大量的可能启动子组合中排列出唯一的启动子区域．

γ-分泌酶抑制剂DAPT抑制Jurkat T细胞增殖

目的:探讨γ-分泌酶抑制剂DAPT在体外对人T淋巴细胞白血病JurkatT细胞株增殖的抑制作用及其某些机制。方法:通过倒置显微镜和MTT法检测DAPT对Jurkat T细胞聚集的影响和对其增殖的抑制作用;利用碘化丙锭染色结合流式细胞术检测DAPT对Jurkat T细胞周期的影响;藉免疫印迹法检测DAPT对Jurkat T细胞周期蛋白ICBP90表达的影响。结果:DAPT能显著影响Jurkat T细胞的聚集,抑制Jurkat T细胞的增殖,使其细胞周期停滞于S期,且周期蛋白ICBP90的表达下调。结论:γ-分泌酶抑制剂DAPT能够抑制Jurkat T细胞的增殖和细胞周期的进行,其抑制作用可能与ICBP90蛋白表达的下调有关。

上调叉头框转录因子J2对肺癌细胞凋亡及CHOP蛋白表达的影响

目的:探讨上调叉头框转录因子J2(Foxj2.对肺癌细胞凋亡和CCAAT/增强子结合蛋白同源蛋白(CHOP)表达的影响。方法:用qRT-PCR和Western blot法检测肺癌A549、H1299、SPCA1细胞和正常肺HBE细胞中Foxj2 mRNA和蛋白的表达情况。SPCA1细胞分别感染pLV-EGFP-Foxj2慢病毒(Foxj2组)和pLV-EGFP对照慢病毒(阴性对照组),以未感染细胞为空白对照。48 h后,采用qRT-PCR和Western blot法检测Foxj2 mRNA和蛋白的表达,采用MTT法检测细胞增殖,Annexin V-FITC/PI双染法检测细胞凋亡,Western blot法检测细胞中活化转录因子4(ATF4)、活化的Caspase-3(Cleaved Caspase-3)、CHOP、Bax蛋白表达水平。结果:肺癌A549、H1299、SPCA1细胞中Foxj2 mRNA和蛋白表达水平均低于正常肺HBE细胞(P均<0.05)。与阴性对照组和空白对照组相比,Foxj2组SPCA1细胞中Foxj2 mRNA和蛋白的表达水平升高,细胞存活率降低,凋亡率升高,细胞中ATF4、Cleaved Caspase-3、CHOP、Bax蛋白表达水平升高(P均<0.05)。结论:Foxj2在肺癌细胞中表达水平降低;上调Foxj2的表达可能通过内质网途径诱导肺癌细胞凋亡。

结肠癌病灶内C/EBPα、FOXC2表达量的研究及其下游靶基因的初步分析

目的:研究结肠癌病灶内C/EBPα、FOXC2的表达量并探究其下游靶基因。方法:选择2014年3月~2017年2月期间在陕西省渭南市中心医院手术切除的结肠癌标本,另取距肿瘤病灶边缘5cm以上的癌旁组织标本作为对照。抽提临床标本中的RNA并测定C/EBPα、FOXC2以及内质网应激分子、上皮间质转化分子的mRNA表达量。结果:结肠癌标本中C/EBPα、Bax、Bak、GRP78、PERK、ATF6的mRNA表达量显著低于癌旁标本,FOXC2、FAK、SphK1、N-cadherin、Vimentin的mRNA表达量显著高于癌旁标本;C/EBPα高表达的结肠癌标本中Bax、Bak、GRP78、PERK、ATF6的mRNA表达量显著高于C/EBPα低表达的结肠癌标本;FOXC2高表达的结肠癌标本中FAK、SphK1、N-cadherin、Vimentin的mRNA表达量显著高于FOXC2低表达的结肠癌标本。结论:结肠癌病灶内低表达的C/EBPα和高表达的FOXC2分别能够抑制内质网应激所介导的细胞凋亡、促进上皮间质转化所介导的细胞侵袭。

A Major QTL, Ghd8, Plays Pleiotropic Roles in Regulating Grain Productivity, Plant Height, and Heading Date in Rice

Rice yield and heading date are two distinct traits controlled by quantitative trait loci （QTLs）. The dissection of molecular mechanisms underlying rice yield traits is important for developing high-yielding rice varieties. Here, we report the cloning and characterization of Ghd8, a major QTL with pleiotropic effects on grain yield, heading date, and plant height. Two sets of near isogenic line populations were developed for the cloning of GhdS. Ghd8 was narrowed down to a 20-kb region containing two putative genes, of which one encodes the OsHAP3 subunit of a CCAAT-box binding protein （HAP complex）; this gene was regarded as the Ghd8 candidate. A complementary test confirmed the identity and pleiotropic effects of the gene; interestingly, the genetic effect of Ghd8 was dependent on its genetic background. By regulating Ehdl, RFT1, and Hd3a, Ghd8 delayed flowering under long-day conditions, but promoted flowering under short-day conditions. Ghd8 up-regulated MOC1, a key gene controlling tillering and branching; this increased the number of tillers, primary and secondary branches, thus producing 50% more grains per plant. The ectopic expression of Ghd8 in Arabidopsis caused early flowering by 10 d-a situation similar to the one observed by its homolog AtHAP3b, when compared to wild-type under long-day conditions; these findings indicate the conserved function of Ghd8 and AtHAP3b in flowering in Arabidopsis. Our results demonstrated the important roles of Ghd8 in rice yield formation and flowering, as well as its opposite functions in flowering between rice and Arabidopsis under long-day conditions.

LHD1,an Allele of DTH8/Ghd8,Controls Late Heading Date in Common Wild Rice (Oryza rufipogon)

Flowering at suitable time is very important for plants to adapt to complicated environments and produce their seeds successfully for reproduction. In rice （Oryza rufipogon Griff.） photoperiod regulation is one of the important factors for controlling heading date. Common wild rice, the ancestor of cultivated rice, exhibits a late heading date and a more sensitive photoperiodic response than cultivated rice. Here, through map-based cloning, we identified a major quantitative trait loci （QTL） LHD1 （Late Heading Date 1）, an allele of DTH8/Ghd8, which controls the late heading date of wild rice and encodes a putative HAP3/NF-YB/CBF-A subunit of the CCAAT-box-binding transcription factor. Sequence analysis revealed that several variants in the coding region of LHD1 were correlated with a late heading date, and a further complementary study successfully rescued the phenotype. These results suggest that a functional site for LHD1 could be among those variants present in the coding region. We also found that LHD1 could down-regulate the expression of several floral transition activators such as Ehdl, Hd3a and RFT1 under long-day conditions, but not under short-day conditions. This indicates that LHD1 may delay flowering by repressing the expression of Ehdl, Hd3a and RFT1 under long-day conditions.