Embryonic expression pattern of a family of Drosophila proteins that interact with a central nervous system regulatory element

The protein Elf-1 interacts with a cis-acting element that is required specifically for the neuronal expression of the Drosophila dopa decarboxylase gene Ddc. Using protein purified from Drosophila embryos, we raised Elf-1-specific monoclonal antibodies. The expression of Elf-1 during embryogenesis is restricted to nuclei of tissues derived from ectoderm, predominantly the central nervous system (CNS) and the epidermis. Within the CNS, Elf-1 is present in only a small fraction of nuclei, and the pattern of expressing nuclei changes dramatically during development. Elf-1 and Ddc are coexpressed in primary cultures of neural cells. However, we do not detect Elf-1 in Ddc-expressing neurons in vivo, leading to the suggestion that Elf-1 activity is required in vivo for initiation of Ddc expression but not for its maintenance. The antibodies also were used to isolate cDNA clones encoding Elf-1. Alternate forms of Elf-1 mRNA result in at least three protein isoforms.     

Regulation of the Drosophila dopa decarboxylase gene in neuronal and glial cells

A cis-regulatory element selectively required for the Drosophila melanogaster dopa decarboxylase gene (Ddc) in the central nervous system has been identified previously (Scholnick et al. 1986). Here, we show that at least one additional regulatory element is required for normal neuronal expression of Ddc. We find that Ddc is normally expressed in about 125 discrete neurons and in a diffused network comprising a subset of glial cells. The expression of in vitro-altered Ddc genes was studied by immunohistochemistry following germ line reintegration with P-element vectors. Normal neuron-specific Ddc gene expression requires both the initially identified element (element I) which is 60 bp upstream from the RNA start site, and an additional regulatory element located 800-2200 bp upstream. This latter element is required for neuronal expression but is not necessary for glial expression of Ddc. We provide a model to explain how interactions between multiple regulatory elements may serve to specify cell-specific gene expression.     

A neuron-specific enhancer of the Drosophila dopa decarboxylase gene

At least two cis-regulatory elements are necessary for correct neuron-specific expression of the Drosophila melanogaster dopa decarboxylase gene, Ddc. In addition to a previously described proximal element located approximately 60 bp upstream of the mRNA start site, we have now characterized a distal approximately 600-bp DNA fragment, extending from -1019 to -1623 bp, which possesses enhancer-like properties and is essential for normal neuron-specific expression. Immunofluorescent labeling of neurons expressing deleted Ddc genes indicates that this region contains both general neuronal regulatory elements and cell-specific elements that selectively affect Ddc expression in either dopaminergic or serotonergic neurons. These selective effects can be correlated with the removal of sequence elements that are protected from DNase digestion by factors present in embryonic nuclear extracts. Several of these elements are also homologous to sequences located upstream of the evolutionarily diverged Ddc gene of Drosophila virilis. These results suggest that the neuron-specific expression of Ddc results from the combined action of several factors binding within this distal enhancer region.     

转录因子 Elf-1在上皮性卵巢癌中的表达及其意义

目的 探讨转录因子Elf-1在上皮性卵巢癌中的表达及其临床意义,并探讨Elf-1与卵巢癌细胞增殖的相关性.方法 收集31例上皮性卵巢肿瘤组织及3例正常卵巢组织标本,采用免疫组化S-P法测定Elf-1在上皮性卵巢癌中的表达并对其表达情况进行分析.结果 在23例上皮性卵巢癌组织中Elf-1阳性表达15例(65.22%).Elf-1的表达与组织学类型有关(χ2=6.54,P＜0.05),与患者的年龄、FIGO临床分期差异无统计学意义(χ2=0.25和0.08,P＞0.05).Elf-1在上皮性卵巢癌中的表达与c-Fos在上皮性卵巢癌中的表达呈正相关(Kappar=0.39,P＞0.05).结论 Elf-1在上皮性卵巢癌组织中呈高水平表达,且与原癌基因c-Fos的表达呈正相关,提示Elf-1可能通过影响上皮性卵巢癌细胞的增殖而参与其发生和发展.     

转录因子Elf-1在上皮性卵巢癌中的表达及其意义

目的探讨转录因子Elf-1在上皮性卵巢癌中的表达及其临床意义,并探讨Elf-1与卵巢癌细胞增殖的相关性。方法收集31例上皮性卵巢肿瘤组织及3例正常卵巢组织标本,采用免疫组化S-P法测定Elf-1在上皮性卵巢癌中的表达并对其表达情况进行分析。结果在23例上皮性卵巢癌组织中Elf-1阳性表达15例（65．22％）。Elf-1的表达与组织学类型有关（χ2=6．54,P〈0．05）,与患者的年龄、FIGO临床分期差异无统计学意义（χ2=0．25和0．08,P〉0．05）。Elf-1在上皮性卵巢癌中的表达与c-Fos在上皮性卵巢癌中的表达呈正相关（Kappar=0．39,P〉0．05）。结论Elf-1在上皮性卵巢癌组织中呈高水平表达,且与原癌基因c-Fos的表达呈正相关,提示Elf-1可能通过影响上皮性卵巢癌细胞的增殖而参与其发生和发展。     

脐带血CD4~+和CD8~+ T细胞中T细胞特异转录因子Elf-1表达特点

目的:了解脐带血单个核细胞(CBMCs)及其CD4+和CD8+ T细胞亚群中转录因子Elf-1的表达特点。方法:采用SYBR GreenⅠ荧光定量PCR和相对定量分析法检测12例脐带血CBMCs、CD4+和CD8+ T细胞亚群中Elf-1基因的表达情况,以β2微球蛋白基因(β2M)作为内参照,10例健康成人作为对照,采用相对定量公式:2-△Ct×100%,计算Elf-1mRNA相对表达量。结果:脐带血和健康成人外周血单个核细胞(PBMC)、CD4+和CD8+ T细胞均表达Elf-1,具体表达量呈现明显的个体差异性。Elf-1 mRNA相对表达量在CBMCs为18.55%±2.48%(其中最高为36.22%,最低为6.45%),在脐带血CD8+ T细胞为3.52%±0.45%(其中最高为6.75%,最低为1.71%),均明显高于健康成人PBMC(9.16%±1.92%)及其CD8+ T细胞(2.02%±0.27%)(P0.01,P0.05),而脐带血CD4+T细胞Elf-1 mRNA相对表达量为3.83%±0.61%,与健康成人外周血CD4+ T细胞(2.73±0.52%)比较,无显著差异。结论:本研究率先报道脐带血T细胞亚群中Elf-1 mRNA表达特点,结果提示Elf-1基因在CBMCs及其CD8+ T细胞亚群中的高表达可能是T细胞的免疫学特点之一。