Preparation of a differentially expressed, full-length cDNA expression library by RecA-mediated triple-strand formation with subtractively enriched cDNA fragments

We have developed a fast and general method to obtain an enriched, full-length cDNA expression library with subtractively enriched cDNA fragments. The procedure relies on RecA-mediated triple-helix formation of single-stranded cDNA fragments with a double-stranded cDNA plasmid library. The complexes were then captured from the solutions using the digoxigenin-antidigoxigenin paramagnetic beads followed by recovery of the enriched double-stranded cDNA expression library. We have observed a linear relation between the capture of full-length cDNAs in the library and the fold enrichment in the subtracted cDNA population.     

Cloning and functional expression of a Schistosoma japonicum cDNA homologous to the enolase gene family

A cDNA encoding the complete open reading frame of Schistosoma japonicum enolase has been cloned. The 1494bp cDNA (C30) was isolated from a S. japonicum cDNA expression library immunoscreened with hyperimmune rabbit sera raised against soluble adult S. japonicum proteins. The ORF encodes a protein of 434 amino acids exhibiting 72% identity to human, murine, and rat enolases, and 62% identity to Saccharomyces cerevisiae enolase. The inferred molecular mass of the protein is 47,251 Daltons, similar to that reported for the enolases of other species. In vitro translation of C30 also generated a protein of 47kDa. After subcloning and expression, the recombinant protein was purified by affinity chromatography under non-denaturing conditions and shown to exhibit functional enolase enzymatic activity.     

Quantitative trait locus mapping of human blood pressure to a genetic region at or near the lipoprotein lipase gene locus on chromosome 8p22

Resistance to insulin-mediated glucose disposal is a common finding in patients with non-insulin-dependent diabetes mellitus (NIDDM), as well as in nondiabetic individuals with hypertension. In an effort to identify the generic loci responsible for variations in blood pressure in individuals at increased risk of insulin resistance, we studied the distribution of blood pressure in 48 Taiwanese families with NIDDM and conducted quantitative sib-pair linkage analysis with candidate loci for insulin resistance, lipid metabolism, and blood pressure control. We found no evidence for linkage of the angiotensin converting enzyme locus on chromosome 17, nor the angiotensinogen and renin loci on chromosome 1, with either systolic or diastolic blood pressures. In contrast, we obtained significant evidence for linkage or systolic blood pressure, but not diastolic blood pressure, to a genetic region at or near the lipoprotein lipase (LPL) locus on the short arm of chromosome 8 (P = 0.002, n = 125 sib-pairs, for the haplotype generated from two simple sequence repeat markers within the LPL gene). Further strengthening this linkage observation, two flanking marker loci for LPL locus, D8S261 (9 cM telomeric to LPL locus) and D8S282 (3 cM centromeric to LPL locus), also showed evidence for linkage with systolic blood pressure (P = 0.02 and 0.0002 for D8S261 and D8S282, respectively). Two additional centromeric markers (D8S133, 5 cM from LPL locus, and NEFL, 11 cM from LPL locus) yielded significant P values of 0.01 and 0.001, respectively. Allelic variation around the LPL gene locus accounted for as much as 52-73% of the total interindividual variation in systolic blood pressure levels in this data set. Thus, we have identified a genetic locus at or near the LPL gene locus which contributes to the variation of systolic blood pressure levels in nondiabetic family members at high risk for insulin resistance and NIDDM.     

The murine CYLN2 gene: genomic organization, chromosome localization, and comparison to the human gene that is located within the 7q11.23 Williams syndrome critical region

Several agents that act through G-protein-coupled receptors and also stimulate phosphoinositide-specific phospholipase C (PI-PLC), including angiotensin II, vasopressin, norepinephrine, and prostaglandin (PG) F2alpha, activated the ERK1 (p44mapk) and ERK2 (p42mapk) members of the mitogen-activated protein (MAP) kinase family in primary cultures of rat hepatocytes, measured as phosphorylation of myelin basic protein (MBP) by a partially purified enzyme, immunoblotting, and in-gel assays. All these agonists induced a peak activation (two to threefold increase in MBP-phosphorylation) at 3-5 min, followed by a brief decrease, and then a sustained elevation or a second increase of the MAP kinase activity that lasted for several hours. Although all the above agents also stimulated PI-PLC, implicating a Gq-dependent pathway, the elevations of the concentration of inositol (1,4,5)-trisphosphate did not correlate well with the MAP kinase activity. Furthermore, pretreatment of the cells with pertussis toxin markedly reduced the MAP kinase activation by angiotensin II, vasopressin, norepinephrine, or PGF2alpha. In addition, hepatocytes pretreated with pertussis toxin showed a diminished MAP kinase response to epidermal growth factor (EGF). The results indicate that agonists acting via G-protein-coupled receptors have the ability to induce sustained activation of MAP kinase in hepatocytes, and suggest that Gi-dependent mechanisms are required for full activation of the MAP kinase signal transduction pathway by G-protein-coupled receptors as well as the EGF receptor.     

Molecular cloning and functional expression of a cDNA for rat phospholipid hydroperoxide glutathione peroxidase: 3'-untranslated region of the gene is necessary for functional expression

A full-length cDNA clone for phospholipid hydroperoxide glutathione peroxidase (PHGPx) was isolated from a rat brain. The cDNA was 0.761 kb in length and encoded 170 amino acids, which included a TGA-encoded selenocysteine at residue 46. The protein has a calculated molecular mass of 19,473 Da. We succeeded in the transient functional expression of a full-length cDNA for PHGPx, which includes the 3'-UTR, in COS-7 cells at the first attempt. Deletion of the 3'-UTR prevented the expression of the PHGPx activity and the incorporation of [75Se]selenious acid into the monomeric 19.7 kDa PHGPx protein. Thus, the 3'-UTR of the cDNA for PHGPx was required for the functional expression of PHGPx. Northern blot analysis demonstrated that the mRNA for PHGPx was widely expressed in normal rat tissues, especially in the testis. The mRNA levels of PHGPx in the cultured cells such as hepatomas, neuronal cells, nephroblastoma, and mammary myo-epithelial cells were higher than those of the tissues. The ratio of PHGPx to cytosolic glutathione peroxidase (cGPx) was significantly high in the testis and relatively high in the cultured cells. The mRNA levels of PHGPx in tissues were lower than those of cGPx.     

cDNA cloning and expression analysis of the murine ribonuclease L inhibitor

This study was designed to test the hypothesis that the immune changes seen during in vivo whole body hyperthermia are mediated by elevations in the plasma concentrations of either catecholamines, growth hormone or beta-endorphins. Eight healthy volunteers were immersed in a hot water bath (WI; water temperature 39.5 degrees C) for 2 h during which their rectal temperature rose to 39.5 degrees C. In a single blind, randomized, cross-over study the stress hormone effects were blocked one at a time by administration of propranolol, somatostatin or naloxone; the results were compared to those obtained during saline infusion (control). Blood samples were collected before, at the end of 2 h of WI (body temperature 39.5 degrees C), and 2 h later. Hormone blockade did not abolish the hyperthermia-induced recruitment of natural killer (NK) cells to the blood, and no influence was observed on the percentages or concentrations of any other subpopulations of blood mononuclear cells, except that the number of cluster designation (CD)3+ cells slightly increased after hyperthermia only in the propranolol experiment. Furthermore, the NK cell activity, both unstimulated and interferon-alpha or interleukin-2 stimulated, did not differ from the control situation. It is of interest, however, that somatostatin partly abolished the hyperthermia induced increase in the neutrophil number. Based on these data and previous results showing that growth hormone infusion increases the concentration of neutrophils in the blood, it is suggested that growth hormone is at least partly responsible for hyperthermia induced neutrocytosis.     

水稻PHD锌指蛋白cDNA的克隆及其表达分析

利用cDNA-AFLP分析籼稻明恢86应答稻纵卷叶螟取食基因差异表达,发现1个与植物同源结构域(PHD)锌指蛋白高度同源的TDF,分离获得该TDF对应的粳稻全长cDNA.该全长cDNA与籼稻、玉米、蓖麻、葡萄、拟南芥和大豆等作物PHD锌指蛋白推定氨基酸序列的同源性分别为98.43%、86.01%、54.58%57.02%、57.51%和55.88%.荧光定量PCR研究表明,日本晴(粳稻)叶片中该基因的表达也受稻纵卷叶螟取食的诱导,推测该基因与籼稻和粳稻应答稻纵卷叶螟取食密切相关.     

cDNA cloning and gene expression of phenylalanine ammonia-lyase in Lithospermum erythrorhizon

Two cDNA clones (LEPAL-1 and LEPAL-2) encoding phenylalanine ammonia-lyase were isolated from cell suspension cultures of Lithospermum erythrorhizon. Northern kinetic studies showed that LEPAL-1 mRNA contents markedly increased one day after inoculation of the cells into fresh medium, then decreased to the steady-state level. The course of mRNA accumulation paralleled that of PAL enzyme activity. The rapid induction of PAL activity seems to reflect the induction of dihydroechinofuran biosynthesis, while shikonin was produced at the steady-state level of PAL activity. The course of LEPAL-2 mRNA accumulation seemed to be similar to, but much lower than that of LEPAL-1. In the intact plant, both genes are expressed mainly in the root, the organ in which shikonin is exclusively produced and accumulated. Genomic Southern blot analyses showed that both genes are present in the genome as single copies.     

Identification of a self-association region within the SCA1 gene product, ataxin-1

OBJECTIVES: To report the association between the protease inhibitor indinavir and the development of urolithiasis. METHODS: Case reports of three adult patients infected with the human immunodeficiency virus who developed surgical renal stones while being treated with indinavir are presented. RESULTS: Of the 3 patients requiring surgical intervention, stone analyses were available in 2. One stone revealed an inner core of an unidentifiable crystal surrounded by calcium oxalate, and another was found to have indinavir components as determined by thin-layer chromatography and gas chromatography-mass spectrometry. Metabolic evaluation of all 3 patients identified significant hypocitraturia as an isolated finding. CONCLUSIONS: The widely used protease inhibitor indinavir is associated with the development of urolithiasis and may act as a nidus for heterogeneous nucleation leading to the development of mixed urinary stones. Surgical intervention may be necessary in some cases. Underlying metabolic abnormalities may contribute to the increased incidence of stone formation. Urologists and other health care providers should be aware of this association, as combined medical and surgical intervention may be necessary.     

Subdomain structure of the matrix attachment region located within the mouse immunoglobulin kappa gene intron

Using the matrix attachment region (MAR) derived from Ig kappa gene intron, we assessed the importance of internal subregions required for the specific binding to the nuclear matrix. Relative affinities of MAR subfragments were compared in an in vitro binding reaction with isolated matrix. Cleavage at the near-centric MboII site generated two subfragments retaining a significant binding affinity. Dimerization of these subfragments greatly increased the affinity. Only a partial segment (130 bp) of the 3' fragment was necessary to restore the binding. The dimerization effect was lost when the monomer units were separated by nonMAR spacers of 500 bp <. This bipartite organization of Ig kappa MAR could be a general feature of AT-rich MARs, regardless of their genomic locations.     

Multiplex-PCR-based single-strand conformation polymorphism protocol for simultaneous analysis of up to five fragments of the low-density-lipoprotein receptor gene

Single-strand conformation polymorphism has become a screening method for the detection of mutations in different genes. For analysis of the promotor region and the coding sequence of the low-density-lipoprotein receptor gene by standard protocols, 21 radiolabeled PCRs and electrophoreses have to be performed. To accelerate this procedure, we developed a nonradioactive multiplex approach of the single-strand conformation polymorphism analysis. Multiplex PCRs were established, each resulting in the amplification of 4 or 5 fragments of this gene. The heat-denatured, single-stranded multiplex-PCR products were electrophoresed, blotted on a nylon membrane and visualized using a chemiluminescence detection system. The simultaneously amplified fragments were clearly resolved by their different mobility on the gel. Comparing the pattern of bands of each separately amplified PCR product and the multiplex-PCR products allowed identification of each band as one exon, part of an exon or the promotor region of the gene. To determine the sensitivity of this method, the low-density-lipoprotein receptor gene of 11 patients with 11 different mutations was analyzed. All mutations could be identified in the multiplex reactions. We conclude that a multiplex-PCR-based, single-strand conformation polymorphism protocol is much faster but equally sensitive compared to standard protocols.     

Analysis of elastin gene expression in the developing chick aorta using cloned elastin cDNA

A segment of chick elastin cDNA cloned in the plasmid pBR322 was sequenced by the method of Maxam and Gilbert ((1977) Proc. Natl. Acad. Sci. U. S. A. 74, 560-564) and the 192-base pair insert was found to be derived from the nontranslated region of the 3' end of the mRNA. The nick-translated cDNA was used to identify and to estimate the relative amounts of elastin mRNA in the developing chick embryo aorta by blot hybridization. A single species of 3.5 kilobases hybridized to the cDNA probe and this species increased greatly between day 7 and day 14 of embryonic development. This increase was paralleled by an increase in translatable aortic elastin mRNA and by the in vivo rate of elastin synthesis, demonstrating that the change in synthesis during development is largely controlled by the elastin mRNA content of the aorta.