A human glial hybrid cell line differentially expressing genes subserving oligodendrocyte and astrocyte phenotype

We have developed a series of immortal human-human hybrid cell lines that express phenotypic characteristics of primary oligodendrocytes, by fusing a 6-thioguanine–resistant mutant of the human rhabdomyosarcoma RD with adult human oligodendrocytes by a lectin-enhanced polyethylene glycol procedure. Hybrids were selected in an aminopterin-containing media. In contrast to the tumor parent cells, a hybrid clone M03.13 expressed surface immunoreactivity for galactosyl cerebroside and intracellular immunoreactivity for myelin basic protein (MBP), proteolipid protein (PLP), and glial fibrillary acidic protein (GFAP). Serum deprivation or chronic treatment with a protein kinase C activator 4-β-phorbol 12-myristate 13-acetate (PMA), but not dibutyl cyclic adenosine monophosphate induced coordinate up-regulation or de novo induction of oligodendrocyte phenotypic markers with concomitant down-regulation of GFAP expression. Consistent with immunohistochemical studies, northern blot analysis demonstrated that both MBP and PLP mRNA were up-regulated in MO3.13 cells by PMA treatment. M03.13 cells provide an immortalized clonal model system suitable for study of gene expression subserving oligodendrocyte and astrocyte phenotypes. © 1995 John Wiley & Sons, Inc.     

Recognition of HLA-A2 mutant and variant target cells by an HLA-A2 allospecific human cytotoxic T lymphocyte line

HLA-A2 specific human cytotoxic T lymphocytes (CTL) cell lines have been developed using T cell growth factor and coculture of peripheral blood lymphocytes with selected allogeneic target cell lines. The CTL-8 line showed specificity for human leukocyte antigens (HLA)-A2 bearing target cells after 5 weeks in culture when tested against a panel of 14 lymphoblastoid cell lines in a 51Chromium (51Cr) release assay. Purified anti-human leukocyte antigens (HLA) monoclonal antibodies W6/32 and PA2.1 inhibited cytolysis by 85% and 60%, respectively. The CTL-8 line lysed non-HLA-A2 target cells in the presence of lectins concanavalin A (Con A) or phytohemagglutinin-P lectin (PHA-P) indicating the specificity of cytolysis was not due to nonspecific resistance of target cells to the CTL-lytic mechanism. The T5-1 HLA-A2 mutant cell series were tested as targets for the CTL-8 line. Cell clones 8.18.1, 8.21.1 and 8.6.1, which express altered HLA-A2 molecules as determined by their decreased reactivity with allospecific monoclonal antibodies, were lysed by the CTL-8 line as efficiently as the T5-1 wild type. These cell lines also acted as efficient cold target competitors for a normal HLA-A2 target cell. The 8.14.1 cell clone expressed a lower amount of HLA-A2 alloantigen and showed a corresponding decreased reactivity with CTL-8 in direct cytolytic and cold target competitive inhibition assays. In contrast, the M7 and DK1 HLA-A2 variant cell lines, which express normal HLA-A2 serological determinants, were inefficiently lysed by CTL-8 and did not act as competitive inhibitors of normal HLA-A2 target cells. These results support the concept that the alloantigenic determinant(s) recognized by T cells and antibodies occur at separate regions on the HLA-A2 molecule.     

Antigen and haplotype frequencies at three human leucocyte antigen loci (HLA-A, -B, -C) in the Pawaia of Papua New Guinea

The genetic profile of the Pawaia, a seminomadic, linguistic isolate from the highlands fringe of Papua New Guinea, is described in terms of antigen and haplotype frequencies at three class I human leucocyte antigen loci (HLA-A, -B, and -C). The Pawaia, like other Papua New Guinea populations, exhibit restricted polymorphisms at all three loci studied, both in the number of alleles segregating and in the level of average heterozygosity. An extremely high frequency (52.9%) of HLA-B27, the antigen implicated in the pathogenesis of seronegative arthropathies, was found. A novel HLA-C locus specificity, CNG, resulting probably from a gene duplication event, was also observed in significant numbers. Although the gene frequency comparisons suggest their strong affinities with the highlanders, the Pawaia haplotypes reveal significant admixture from other neighbouring groups as well. The usefulness of HLA haplotypes in tracing the movements of human populations in the New Guinea area is discussed.     

Polymorphism of HLA class I loci HLA-A, -B, -C, in the Mandenka population from eastern Senegal]

A sample of 162 Mandenkalu from Eastern Senegal has been typed for three HLA class I loci: HLA-A, -B and -C. The Mandenka population presents a very high genetic variability with 15 alleles for locus A, 24 alleles for locus B, and at least 8 alleles for locus C. The calculated heterozygosities for the three loci A, B, and C are respectively 0.884, 0.944 and 0.829. The Mandenkalu allelic frequencies are close to that found in other sub-Saharan populations. They show, however, some peculiarities like the occurrence of the Bw 56 allele and the high frequencies of both B5 and B35.     

Evolutionary implications of the human aldolase-A, -B, -C, and -pseudogene chromosome locations.

The aldolase genes represent an ancient gene family with tissue-specific isozymic forms expressed only in vertebrates. The chromosomal locations of the aldolase genes provide insight into their tissue-specific and developmentally regulated expression and evolution. DNA probes for the human aldolase-A and -C genes and for an aldolase pseudogene were used to quantify and map the aldolase loci in the haploid human genome. Genomic hybridization of restriction fragments determined that all the aldolase genes exist in single copy in the haploid human genome. Spot-blot analysis of sorted chromosomes mapped human aldolase A to chromosome 16, aldolase C to chromosome 17, the pseudogene to chromosome 10; it previously had mapped the aldolase-B gene to chromosome 9. All loci are unlinked and located on to two pairs of morphologically similar chromosomes, a situation consistent with tetraploidization during isozymic and vertebrate evolution. Sequence comparisons of expressed and flanking regions support this conclusion. These locations on similar chromosome pairs correctly predicted that the aldolase pseudogene arose when sequences from the aldolase-A gene were inserted into the homologous aldolase location on chromosome 10.     

Human T cell receptor-gamma delta-expressing T-cell lines recognize MHC-controlled elements on autologous EBV-LCL that are not HLA-A, -B, -C, -DR, -DQ, or -DP.

HLA-loss variants of an EBV-transformed B lymphoblastoid cell line (EBV-LCL) 721 were used to investigate whether human MHC molecules other than known class I or class II were involved in autologous T cell responses. Bulk lymphocyte cultures of purified T cells primed to an autologous variant EBV-LCL that fails to express HLA-class II and has reduced cell surface HLA-class I expression, and oligoclonal TCR-gamma delta-bearing lines derived from them, could lyse both this EBV-LCL and an independently derived, class II expressing autologous variant EBV-LCL that bears no HLA-A, -B, or -C, suggesting the presence of additional HLA-like restriction elements. Cold target inhibition of cytolysis mediated by these lines indicated that a shared or cross-reactive MHC controlled restriction element other than the known MHC determinants was retained by the EBV-LCL variants. Single-cell derived clones from these T cell lines which expressed only the TCR-gamma delta showed this same target cell specificity pattern, proving recognition of MHC-controlled determinants by autologous gamma delta T cells. Anti-gamma delta antibody could inhibit cytolysis by the gamma delta-expressing lines, suggesting that the TCR-gamma delta was involved in recognition of the EBV-LCL targets. Flow cytometric analysis with separate HLA-reactive antibodies indicated that the restriction element for these cytolytic responses is a molecule serologically cross-reactive with HLA-B and -C Ag, yet is a determinant that cannot be HLA-A, -B, -C, -DR, -DQ or -DP.     

The yliA, -B, -C, and -D genes of Escherichia coli K-12 encode a novel glutathione importer with an ATP-binding cassette

Glutathione protects cells and organisms from oxygen species and peroxides and is indispensable for aerobically living organisms. Moreover, it acts against xenobiotics and drugs by the formation and excretion of glutathione S conjugates. In this study, we show that the yliA, -B, -C, and -D genes of Escherichia coli K-12 encode a glutathione transporter with the ATP-binding cassette. The transporter imports extracellular glutathione into the cytoplasm in an ATP-dependent manner. This transporter, along with gamma-glutamyltranspeptidase, has an important role in E. coli growth with glutathione as a sole sulfur source.     

Production of transgenic embryos through nuclear transfer using ovine fetal fibroblasts transferred with foreign genes

Human ALR gene sequence was amplified by PCR from human total DNA and inserted into pIRES(2)-EGFP vector. The bicistronic eukaryotic expression vector, pIRES-EGFP/ALR, expressing EGFP, Neo(r) and ALR genes was constructed. Sheep fetal fibroblast cells (sEFCs) were transfected with pIRES-EGFP/ALR by the induction of lipofectAMINE(TM). The positive cell clones were selected with medium containing G418 (800 μg/mL). The fluorescence of transgenic cells was examined with a confocal laser scanning microscope. The expression of ALR gene was tested by PCR, RT-PCR and immuno-histochemical staining. The transgenic cells were used as donors for nuclear transfer to enucleated ovine oocytes. Transgenic embryos were tested by confocal laser scanning microscope and immuno-histochemical staining. Results showed that the EGFP and ALR genes linked with IRES were coexpressed simultaneously in sFFCs; the blastocysts formed by nuclear transfer using tranfected donor cells are all transgenic blastocysts. EGFP, ALR and Neo(r) gene were all expressed in the transgenic embryos. In conclusion that a method to construct the positive embryos before pre-implantation which stably express ALR gene by the indication of EGFP expression has been successfully established. The application of this method can simplify the procedure of testing the targets and contribute to the efficiency increasing of transgenic domestic animal production.     

体细胞核移植生产绵羊转hALR基因囊胚

扩增人肝细胞再生增强因子(human augmenter of liver regeneration,ALR)基因,利用质粒pIRES2-EGFP 构建新霉素(Neo)、增强绿色荧光蛋白(enhanced green fluorescence protein,EGFP)双标记基因且EGFP和ALR基因为双顺反子的真核表达载体.LipofectAMINETM介导其转染体外培养的绵羊胎儿成纤维细胞(sheep fetal fibroblast cells,sFFCs);经G418筛选转基因细胞;激光共聚焦显微镜挑选绿色荧光单克隆细胞.PCR、RT-PCR和免疫组织化学方法进一步检测ALR基因及其表达;稳定表达外源基因的sFFCs作供体,移入去核的绵羊卵母细胞中,进行体细胞核移植.通过激光共聚焦显微镜和ALR抗体检测EGFP、ALR基因在胚胎水平上的表达,其结果表明:由IRES连接的EGFP和ALR基因可在绵羊胎儿成纤维细胞内同时表达,由此细胞核移植产生的转基因胚胎在发育的各阶段均可见绿色荧光;囊胚中所有细胞表达EGFP基因;发绿色荧光的胚胎中ALR基因同时存在.因此,由IRES连接标记基因和目的基因,以标记基因指示目的基因的表达,可简化检测目的基因的繁琐手段;用筛选的转基因早期胚胎进行移植,可提高制备转基因动物的效率.     

Arginase,an s-phase enzyme in a human cell line

Suspension cultures of ‘Chang liver’ cells were synchronized by preincubation in a glutamine-deficient medium or by thymidine blockade. Specific arginase activity varied in the synchronized cultures, being high when the number of S-phase cells was maximal. A relationship between high arginase activity and a high percentage of (S+G₂) cells was also found when unsynchronized cells were separated by velocity sedimentation. The increase in arginase activity near the G₁/S border was totally inhibited in the presence of cycloheximide. The rate of decrease in activity after addition of the drug indicated that the variations in the rate of synthesis of the enzyme, while the rate of degradation was more or less constant, corresponding to 4–6% per h. The role of arginase in cells lacking a urea cycle and the regulation of arginase activity in ‘Chang liver’ cells is discussed.     

Presence of side-population cells in an immortalized nontumorigenic human liver epithelial cell line

Side-population (SP) cells have been shown to be highly enriched stem cells. We investigated whether an immortalized, nontumorigenic human liver cell line, THLE-5b, contains SP cells. Flow cytometry analysis after Hoechst 33342 staining demonstrated that the THLE-5b line contained a small component of SP cells. These SP cells were essentially eliminated by treatment with verapamil and expressed higher levels of ABCG2 mRNA than non-SP cells. In addition, the level of these SP cells detected by Hoechst 33342 staining was affected by the experimental conditions including the incubation medium. This is the first report of the presence of SP cells in the immortalized, nontumorigenic human liver cell line.     

稳定表达hHCN2基因 HEK293细胞系的建立

目的：培育稳定表达hHCN2基因的细胞系,建立一种表达研究心肌离子通道的有效模型。方法：通过脂质体转染的方法,将重组pcDNA3-hHCN2真核表达载体导入人胚肾细胞（HEK293细胞）,以G418压力筛选转染细胞,并对其进行全细胞膜片钳记录。结果：经600μg／ml压力筛选后,获得抗性细胞克隆,并用全细胞膜片钳技术记录到克隆hHCN2通道编码电流。结论：本实验采用脂质体转染法成功地培育出G418抗性HEK293细胞。为进一步研究克隆离子通道结构和功能的关系奠定基础。