人β-簇珠蛋白基因LCR调控元件中HS3与反式调控因子相互作用的研究

人β-簇珠蛋白基因LCR调控元件位于ε-珠蛋白基因5’上游20Kb内,由四个DNase-Ⅰ超敏感点(HS1-HS4)组成。已有转基因实验表明,HS3可能与发育早期的胚胎型ε-珠蛋白基因表达调控相关。基因调控是通过调控元件与调控因子的相互作用而完成的。为了揭示HS3的调控作用,我们选用了发育不同时期的小鼠胚胎造血组织作为材料,用凝胶电泳阻抑法,分析了调控因子与HS3的结合。我们的实验结果表明,怀孕13天和18天的小鼠胚胎造血组织的核蛋白因子与HS3的结合模式完全不同;同时我们用Southwestern Blot的方法进一步证明了这种差异性的存在。现已知HS3中有GA-TA和CACCC两类转录因子结合的motif,采用竞争实验分析,发现CACCC motif对结合区带没有竞争作用,而GATA有竞争作用;另外还存在没有被竞争的条带,我们推测它们可能是一类新的、发育时期专一性的核蛋白因子。Western Blot的实验结果表明,在基因调控过程中起到重要作用的红系转录因子GATA家族中的GATA-1和GATA-2的表达也具有时期专一性:即怀孕13天的小鼠造血组织中表达GATA-2,不表达GATA-1;而怀孕18天的小鼠造血组织中则表达GATA-1,不表达GA-TA-2。因此,我们推测,HS3很可能参与时期专一性的基因表达调控,其中时期专一性的蛋白因子可能起到了重要作用。     

真核基因表达调节的新进展

真核细胞基因的表达受顺式作用的DNA区域(启动子和增强子)和反式作用因子(又称转录活性因子)两方面的调控。诱导性因素可以通过特异性的转录活性因子的产生而发挥作用。转录活性因子与启动子、增强子的DNA核心顺序之间的特异性结合是真核基因表达的组织特异性和发育阶段性的决定性因素。本文综述了近年来真核基因表达调节的新进展,对启动子、增强子和转录活性因子的作用和性质进行了讨论。     

禁食及胰岛素水平对大鼠解偶联蛋白-1、2、3基因表达的影响

 为探讨禁食和胰岛素对解偶联蛋白 - 1、2、3基因 (UCP1 ,2 ,3)表达的影响 ,应用 RT- PCR方法观察了在不同禁食时间和应用胰岛素条件下大鼠白色脂肪组织、棕色脂肪组织和骨骼肌中 UCP1 ,2 ,3m RNA水平的变化 .UCP1基因只在大鼠棕色脂肪组织中表达 .UCP2 ,3基因在三种组织中均有表达 ,在白色脂肪组织中以 UCP2表达为主 ;在骨骼肌中以 UCP3表达为主 .过夜禁食使棕色脂肪组织 UCP1 ,3m RNA水平明显下降 (P<0 .0 1 ) ;UCP2 m RNA水平在三种组织中均呈上升反应 ,以白色脂肪组织中表现最为明显 (P<0 .0 5) ;而对白色脂肪组织和骨骼肌中 UCP3基因表达无明显影响 .禁食时间延长至 48h,除棕色脂肪组织中 UCP2 ,3基因有明显下降外 ,各组织中UCPs基因表达基本调节至正常或高于对照组水平 .胰岛素对 UCPs基因表达水平有一定的上调作用 ,这一作用对棕色脂肪组织 UCPs各基因及骨骼肌中 UCP3基因表现得尤为明显 (P<0 .0 5) .大鼠 UCPs基因表达有一定的组织特异性 ;禁食时间对三种组织中 UCPs各成员基因表达的影响有时相上的区别 ;胰岛素可以调 UCPs各成员基因的表达 .结果反映了 UCPs各成员在能量代谢调节上的不同作用 ,这为理解膳食 -产热与体重调节的关系 ,及其能量代谢平衡与疾病关系提供了实验依据     

牛β-酪蛋白基因控制的人凝血Ⅸ因子基因在小鼠乳腺组织中的表达调控

构建牛β 酪蛋白基因控制的人凝血Ⅸ因子 (hFⅨ )乳腺组织特异性表达载体pCⅨm,pCiⅨ ,pCⅨ和报告基因 (LacZ)乳腺表达载体 pCiLacZ ,pCLacZ ,利用Stearylamine(SA)阳离子脂质体包埋 5种载体 ,通过尾静脉注射的方法直接转染哺乳期母鼠的活体组织 .在DNA ,mRNA以及蛋白质水平对实验小鼠的检测结果表明 :转染处理后hFⅨ基因和LacZ基因在小鼠乳腺获得表达 ,hFⅨ蛋白在乳汁中的最高分泌表达量为 80 .2 8ng/mL ,其中 85 %以上已经羧基化并具有生物学活性 ;对 5种载体表达调控的研究证实牛β_酪蛋白基因 5′端 2 .0kb的片段能够驱动人凝血Ⅸ因子基因在小鼠乳腺组织中分泌表达 ,β_酪蛋白基因内含子 1能够提高Ⅸ因子基因在乳腺组织中的表达水平 ,并能影响该基因表达的组织特异性 ;和hFⅨcDNA相比 ,hFⅨ基因自身的内含子 1能够提高该基因在活体乳腺组织中的表达水平 3倍以上     

非洲爪蟾GATA-1转录因子与爪蟾发育

GATA－1是GATA结合蛋白（GATA－binding protein）家族的成员之一,正向调节红细胞特异性基因的表达,是红系终末分化所必需的因子。与其他物种不同的是,非洲爪蟾GATA－1转录因子具有两业型,两者结构极为相似,但存在功能上的差异,非洲爪蟾GATA－1转录因子在爪蟾发育过程中起着重要的调节作用。     

脊椎动物心脏形态发育的转录调控

转录因子以组织特异性和数量的方式调节基因的表达,是胚胎发育中的主要调节因子.目前已经鉴定了一些特异性调节心脏基因的转录因子,最近又发现显性遗传转录因子的突变能引起人类先天性心脏缺陷,将心脏发育转录因子的研究直接与医学联系起来.尽管这方面的研究已经很广泛了,但心脏发育的转录调控仍不很清楚.本文对心脏转录因子及其作用研究的最新进展进行了综述.     

一种新发现的肌特异基因表达调节因子:心股素

心肌素是一种新发现的特异性调节心肌和平滑肌基因表达的蛋白因子,与血清效应因子(SRF)一起构成肌细胞分化分子开关的组成成分.心肌素在胚胎及成年心肌和平滑肌细胞中均进行表达,是这两类细胞基因特异性表达及分化所必需的转录激活因子.本文就心肌素的结构特征及其调节肌特异基因表达的分子机制进行综述.     

TRPS1在胃癌中的表达及生物信息学分析

目的探究转录抑制因子GATA结合基因1(TRPS1)在胃癌中的表达水平及其与表达相关基因的细胞功能及信号通路。方法通过筛选基因表达谱数据动态分析(GEPIA)、基因芯片表达谱公共数据库(GEO)数据,对TRPS1在胃癌组织中的数据进行Meta分析。采用实时荧光定量PCR技术(RT-qPCR)检测TRPS1在胃癌细胞中的表达水平。应用生物信息学分析TRPS1及表达相似基因的细胞功能和信号通路。结果在公共数据库中,TRPS1在胃癌组织中均呈高表达,合并标准均差SMD为0.40(95%CI:0.04～0.76,P=0.028),敏感性分析稳定,无发表偏倚。TRPS1在胃癌细胞HGC-27和MGC-803中呈高表达(均P0.01)。TRPS1和表达相关基因ESR1富集在多条功能通路中,与转录因子活性、序列特异性DNA结合等肿瘤相关通路密切相关;TRPS1与ESR1存在直接蛋白互作关联。结论 TRPS1在胃癌中可能是一个促癌因子,在胃癌的调控机制中有重要作用。     

载脂蛋白A－Ⅰ基因表达调控的研究进展

载脂蛋白(apolipoprotein,apo)A-Ⅰ是一种重要的血浆蛋白,其基因表达具有明显的组织特异性、种属特异性和发育阶段特异性,Apo A-Ⅰ基因5＇调控区的肝细胞特异性增强子等顺式作用元件同ARP-Ⅰ、HNF-4、RXRα等反式作用因子相作用,调控该基因的特异性表达.     

锌指转录因子GATA4的功能研究进展

先天性心脏病(congenital heart disease,CHD)是常见的先天性缺陷之一,严重危害儿童和成人的健康。锌指转录因子GATA4是心脏形态正常发育的调节因子,贯穿胚胎发育和心脏发育阶段多个表达过程。GATA4的突变会导致多种先天性心脏病的发生,新型GATA4突变(c.A899C,p.K300T)揭示了与房间隔缺陷(ASD)相关的GATA4甲基化位点的突变,拓宽了GATA4基因的突变图谱。GATA4作为心肌细胞生长和心肌发育中的关键参与者,可以调节心肌基因的表达,以应对肥厚性刺激。GATA4通过TRAF3IP2和IL1A激活NF-κB通路,将自噬和DDR联系到衰老和炎症反应。本综述围绕GATA4的结构与功能进行综述,为先天性心脏病的治疗、抗衰老提供一些病理基础或理论参考。     

Divergent expression of claudin -1, -3, -4, -5 and -7 in developing human lung

Background

Claudins are the main components of tight junctions, structures which are associated with cell polarity and permeability. The aim of this study was to analyze the expression of claudins 1, 3, 4, 5, and 7 in developing human lung tissues from 12 to 40 weeks of gestation.

Methods

47 cases were analyzed by immunohistochemisty for claudins 1, 3, 4, 5 and 7. 23 cases were also investigated by quantitative RT-PCR for claudin-1, -3 and -4.

Results

Claudin-1 was expressed in epithelium of bronchi and large bronchioles from week 12 onwards but it was not detected in epithelium of developing alveoli. Claudin-3, -4 and -7 were strongly expressed in bronchial epithelium from week 12 to week 40, and they were also expressed in alveoli from week 16 to week 40. Claudin-5 was expressed strongly during all periods in endothelial cells. It was expressed also in epithelium of bronchi from week 12 to week 40, and in alveoli during the canalicular period. RT-PCR analyses revealed detectable amounts of RNAs for claudins 1, 3 and 4 in all cases studied.

Conclusion

Claudin-1, -3, -4, -5, and -7 are expressed in developing human lung from week 12 to week 40 with distinct locations and in divergent quantities. The expression of claudin-1 was restricted to the bronchial epithelium, whereas claudin-3, -4 and -7 were positive also in alveolar epithelium as well as in the bronchial epithelium. All claudins studied are linked to the development of airways, whereas claudin-3, -4, -5 and -7, but not claudin-1, are involved in the development of acinus and the differentiation of alveolar epithelial cells.     

Expression, purification and osteogenic bioactivity of recombinant human BMP-4, -9, -10, -11 and -14

Bone morphogenetic proteins (BMPs) are cytokines from the TGF-β superfamily, with important roles during embryonic development and in the induction of bone and cartilage tissue differentiation in the adult body. In this contribution, we report the expression of recombinant human BMP-4, BMP-9, BMP-10, BMP-11 (or growth differentiation factor-11, GDF-11) and BMP-14 (GDF-5), using Escherichia coli pET-25b vector. BMPs were overexpressed, purified by affinity his-tag chromatography and shown to induce the expression of early markers of bone differentiation (e.g. smad-1, smad-5, runx2/cbfa1, dlx5, osterix, osteopontin, bone sialoprotein and alkaline phosphatase) in C2C12 cells and in human adipose stem cells. The described approach is a promising method for producing large amounts of different recombinant BMPs that show potential for novel biomedical applications.     

Derivation, characterization, differentiation, and registration of seven human embryonic stem cell lines (VAL-3, -4, -5, -6M, -7, -8, and -9) on human feeder

Derivation of human embryonic stem cell lines has been a remarkable scientific achievement during the last decade. Human embryonic stem cells are regarded as an unlimited cell source for replacement therapy in regenerative medicine. Clearly, the scientific community requires proper derivation, characterization, and registration with the purpose of making them available for research and future medical applications worldwide. In this paper, we report our derivation work as the Valencian Node of the Spanish Stem Cell Bank in the generation, characterization, and registration of VAL-3, -4, -5, -6M, -7, -8, and 9 (www.isciii/htdocs/terapia/terapia_bancocelular.jsp). The derivation process was performed on microbiologically tested and irradiated human foreskin fibroblasts and designed to minimize contact with xeno-components in knockout Dulbecco’s modified Eagle’s medium supplemented with knockout serum replacement and basic fibroblast growth factor. Fingerprinting of the cell lines was performed to allow their identification and traceability. All lines were expressed at the mRNA and specific protein markers for undifferentiation and were found to be negative for classical differentiation markers such as neurofilament heavy chain (ectoderm), renin (mesoderm), and amylase (endoderm). All lines displayed high levels of telomerase activity and were shown to successfully overcome cryopreservation and thawing. Finally, we demonstrated the potential to differentiate in vitro (embryoid body formation) and in vivo (teratoma formation) into cell types from all three germ layers. Teratoma derived from all human embryonic stem cell lines present similar morphological features except VAL-8 that display more aggressive tumor behavior with a larger proportion of solid tissues, as opposed to cyst formation in the other cell lines.     

The synthesis of 13- - - -15, 16-dihydroxyprostaglandins

Both pairs of -ll-desoxy- and -13- - -15, 16-dihydroxyprostaglandins have been synthesized via 1,4-conjugate additions of an appropriately functionalized -vinyl cuprate to the requisite cyclopentenone. These prostaglandin analogs are considerably less potent than PGE₂ as gastric secretion inhibitors or as bronchodilators.     

Copines-1, -2, -3, -6 and -7 show different calcium-dependent intracellular membrane translocation and targeting

The copines are a family of C2- and von Willebrand factor A-domain-containing proteins that have been proposed to respond to increases in intracellular calcium by translocating to the plasma membrane. The copines have been reported to interact with a range of cell signalling and cytoskeletal proteins, which may therefore be targeted to the membrane following increases in cellular calcium. However, neither the function of the copines, nor their actual movement to the plasma membrane, has been fully established in mammalian cells. Here, we show that copines-1, -2, -3, -6 and -7 respond differently to a methacholine-evoked intracellular increase in calcium in human embryonic kidney cell line-293 cells, and that their membrane association requires different levels of intracellular calcium. We demonstrate that two of these copines associate with different intracellular vesicles following calcium entry into cells, and identify a novel conserved amino acid sequence that is required for their membrane translocation in living cells. Our data show that the von Willebrand factor A-domain of the copines modulates their calcium sensitivity and intracellular targeting. Together, these findings suggest a different set of roles for the members of this protein family in mediating calcium-dependent processes in mammalian cells.     

BMP-2、-3、-6和-12在骨肉瘤细胞株中的表达

目的研究骨形态发生蛋白(bone morphogenetic protein,BMP)-2、-3、-6和-12在骨肉瘤细胞株中的表达,为下一步研究BMPs在骨肉瘤发生发展中的作用奠定基础。方法利用免疫细胞化学法和Western blot法检测BMP-2、-3、-6和-12在人骨肉瘤细胞株MG63、U2OS和大鼠骨肉瘤细胞株UMR106中的内源性表达。结果在MG63、U2OS和UMR106细胞中,BMP-2、-3和-6均呈不同程度的阳性表达;而BMP-12在这3株骨肉瘤细胞中则均为阴性,并且两种检测方法所得结果完全一致。结论BMP-2、-3和-6在人骨肉瘤细胞株MG63、U2OS和大鼠骨肉瘤细胞株UMR106中均有内源性表达;而这3株骨肉瘤细胞中均未检出BMP-12的表达。     

Response dynamics of 26-, 34-, 39-, 54-, and 80-kDa proteases in induced cultures of recombinant Escherichia coli

Several researchers have demonstrated that the presence of a heterologous protein in recombinant Escherichia coli elicits a response similar to the heat-shock response, which includes enhanced protease expression. The present work detects, quantifies, and characterizes intracellular protease activity in E. coli that are "shocked" by the induction of a recombinant protein, CAT, which is an endogenous protein in some E. coli strains. A novel, sodium dodecyl sulfate gelatin poly-acrylamide gel electrophoresis (SDS-GPAGE) method is used to detect, quantify, and characterize the presence of these proteases. A hypothesis is proposed which links the amplified protease activity to a temporary depletion of specific amino acid pools, and a stringent-like stress response. (c) 1993 John Wiley & Sons, Inc.