Protein synthesis during the developmental growth of the small and large intestine of the rat.
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ABSTRACT:
SUBMITTER: Goldspink DF
PROVIDER: S-EPMC1153245 | biostudies-other | 1984 Jan
REPOSITORIES: biostudies-other
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Project description:A study is presented of the liver protein gain during the early stages of postnatal development. Fractional rates of protein synthesis and degradation were determined in vivo in livers of 4-day-old mice. At this age, liver protein accumulated at a rate of 18% per day. Synthesis was measured after the injection of massive amounts of radioactive leucine. Degradation was extimated as the balance between synthesis and accumulation of stable liver proteins, or from the disappearance of radioactivity from liver protein previously labelled by the administration of NaH14CO3. We found that the neonatal livers: (1) synthesize 139% as much protein per unit time and unit mass as adult tissue, which is accounted for by a higher ribosome concentration (synthesis per mg of RNA was the same); (2) retain 39% of the newly synthesized protein as stable liver components (compared with 48% in adult mice); (3) degrade protein at 56% of the rate in the adult liver. This lower rate of degradation is quantitatively the most significant difference between the growing and non-growing liver.
| S-EPMC1164963 | biostudies-other
Project description:1. A method is described that allows for measurement of protein synthesis in liver and intestine in the rat. By injecting a massive amount of [14C]leucine (100 mumol/100 g body wt.) an attempt has been made to over come problems of precursor specific radioactivity and problems arising from the breakdown of labelled protein that are encountered when tracer amounts of amino acids are used. 2. Starvation for 2 days resulted in decline in the rate of total liver protein synthesis from 87%/day to 62%/day. 3. In jejunal mucosa the rate of protein synthesis was 136%/day. This declined to 105%/day after 2 days of starvation.
| S-EPMC1186525 | biostudies-other
Project description:Experiment description 1. Experimental design 1) Authors, laboratory, and contact: Xue-Lin Cui1, Patricia Soteropoulos2, Peter Tolias2, Ronaldo P. Ferraris1: 1Dept. of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, NJ 07103-2714, 2Center for Applied Genomics, PHRI, 225 Warren Street Newark, NJ 07103-3506. Contact to Dr. Ronaldo P. Ferraris. 2) Type of the experiment: treated vs. untreated comparison. 3) Experimental factors: Twenty to twenty-two old SD rats were use in the experiment. The intestines of paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h or 20-min, respectively. 4) Totally 14 experiments were done. 5) A common reference was not used for all the hybridizations. 6) Quality control steps ( 14) Miller RA, Galecki A, Shmookler-Reis RJ. Interpretation, design, and analysis of gene array expression experiments. J Gerontol A Biol Sci Med Sci. 2001 Feb;56(2):B52-7. (15) Tseng GC, Oh MK, Rohlin L, Liao JC, Wong WH. Issues in cDNA microarray analysis: quality filtering, channel normalization, models of variations and assessment of gene effects. Nucleic Acids Res. 2001 Jun 15;29(12):2549-57. ( 16) Yang YH, Speed T. Design issues for cDNA microarray experiments. Nat Rev Genet. 2002 Aug;3(8):579-88. (17) Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.): a) In the 4 h perfusion experiment, the intestines of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h, respectively. Totally five replicates were conducted. The RNA samples were extracted from HF- and HG-perfused intestines (n=5 pairs) then labelled with Cy 5 (HF1, HF2, HF3, HF4, and HF5) and Cy 3 (HG1, HG2, HG3, HG4, and HG5), respectively. At the same time, one dye swap experiment, in which the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF1) and Cy 5 (HG1), respectively, was done and used in the data analysis. b) In the 20 min perfusion experiment, the intestines of of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 20-min, respectively. Totally four replicates were conducted. In two of the four-replicate experiments, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 5 (HF1a and HF3a) and Cy 3 (HG1a and HG3a), respectively. In the other two of the four-replicate experiments, the dye was swapped, that is, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF2a and HF4a) and Cy 5 (HG2a and HG4a), respectively. c) Three self-self experiments using different samples (HF1, HG1, and HF2) and one capture primer alone experiment were conducted to eliminate the false positive genes and aid to analyze the data. 7) The goal of the experiment: Fructose induced the expression of GLUT5 mRNA in the small intestinal epithelial cells. But it is not clear about the mechanisms involved in the phenomenal. In this experiment, we hypothesize: the expression of some genes must be changed after fructose perfusion for 4-h, these genes may regulate GLUT5 gene transcription; the expression of some genes must be changed even after 20-min fructose perfusion, these genes may trigger the GLUT5 gene expression as early response gene. Our goal in this study is to find out these potencial gene. 8) Links (URL), citations 2. Samples used, extract preparation, labeling and hybridization 1) Bio-source properties a) Sprague Dawley rats (NCBI taxonomy); b) The rat was anesthetized using urathene. The rat body was kept at 37 oC under light. c) Descriptors relevant to the particular sample: the jejunum of the 20-d old rat pups (unknown sex) was perused. 2) Biomaterial manipulations: the jejunum was in vivo perfused with 100 mM HF or HG for 4-h or 20-min. At the end of each experiment, the jejunum was immediately cut out and snap frozen in liqued nitrogen, and then stored the tissue in -80 oC freezer. 3) RNA isolation: A RNeasy Midi Kit (QIAGEN Inc., Valencia, CA) was used to extract total RNA from the jejunum. The brief procesure is described in the Total RNA Extraction for RT-PCR and Microarray above. 4) Sample assignment to slides for labeling and hybridization: S1: HF1(Cy 5) vs HG1 (Cy 3); S2: HF2 (Cy 5) vs HG2 (Cy 3); S3: HF3 (Cy 5) vs HG3 (Cy 3); S4: HF4 (Cy 5) vs HG4 (Cy 3); S5: HF5 (Cy 5) vs HG5 (Cy 3); S6: HF2 (Cy 3) vs HG2 (Cy 5); S7: HF1a (Cy 5) vs HG1a (Cy 3); S8: HF3a (Cy 5) vs HG3a (Cy 3); S9: HF2a (Cy 3) vs HG2a (Cy 5); S10: HF4a (Cy 3) vs HG4a (Cy 5); S11: HG1 (Cy 5) vs HG1 (Cy 3); S12: HG3 (Cy 5) vs HG3 (Cy 3); S13: HF3 (Cy 5) vs HF3 (Cy 3); S14: Cy 3 vs Cy 5 capture primer. 5) Labeling and hybridization procedures and parameters: The 3DNA Submicro Oligo Expression Array Detection Kit (Genisphere Inc., Hatfield, PA) was employed to synthesize and label the complimentary DNA (cDNA) with fluorescent dye: Cy3 or Cy5. The reason why this indirect labeling method was chosen is based on a previous study which demonstrated that the method was more sensitive and consistent than direct labeling method or other indirect techniques like aminoallyl labeling method and MICROMAX tyramide signal amplification labeling method. (18)Yu J, Othman MI, Farjo R, et al: Molecular Vision 2002; 8:130-137). In the primary experiments, three, four, and five g of total RNA were tested for labeling and hybridization conditions. In the official experiments, four g of total RNA isolated from each sample were used for labeling and hybridization, because the signal to noise ratio is high at this concentration. In addition, at this concentration, all most of the low expressed genes are detectable and the highly expressed genes are not fully saturated. The procedure was conducted following the manufacturer's protocol. Briefly, the first strand cDNA was synthesized using a specific poly T Cy3 RT primer or a specific poly T Cy5 RT primer in different tubes for paired samples. Combine the Cy3 and Cy5 reactions in one tube and precipitate the sample in ethanol. After briefly drying the pellet, resuspend the pellet with 40 l of hybridization buffer. Subsequently, apply the hybridization mixture onto the array slide and hybridize overnight at 55 oC in a humidified chamber. Following the hybridization, the slides were washed by placing them into 50 ml conical tubes containing 2 x SSC, 0.2% SDS for 15 min, 2 x SSC for 10 min, 0.2 x SSC for 10 min, and 95% ethanol for 1 min all at room temperature, except for the first wash, in which the temperature was 42 oC. After drying the slides, the Cy3 and Cy5 capture (connected to dye molecues) reagents mixed in hybridization buffer was pipeted onto the slides, and then hybridize at 65 oC for 3 h following slides wash as described above. 3. Measurement data and spesifications of data processing 1) Raw data description Slides were scanned for Cy3 and Cy5 fluorescence using an Axon GenePix4000 microarray reader (GenePix 4000A, Axon instruments, Foster City, CA) and quantitated using GenePix software. Scan parameters: Scan power: Cy 3 : Cy 5 = 100:100; Laser power: Cy 3 : Cy 5 = 1.15:1.76; Spatial resolution: ???; Pixel size: 10 or 100 ???; Pixel number: F pixels: 50-100; B pixels: 400-500 ???; PMT voltage: 600-750 for Cy 5 channel, 650-850 for Cy 3 channel. 2) Image analysis and quantitation For the image analysis, the density of the spots was detected using Gene Spring (Silicon Genetics, Redwood City, CA) software (GeniPix 4.0) (19) Axon Instruments Inc. (1999) GenePix 4000A User's Guide. Axon Instruments, Union City, CA). It is commercially available. Description of the algorithm and all the parameters used: R = red channel signal = F635; G = green channel signal = B 532; M = log2(R/G); A = 1/2xlog2(RxG); User-difined parameter f = 40%. For the complete image analysis out put of each image, see the NCBI's GEO database (www.ncbi.nlm.nih.gov/geo). 3) Normalized and summarized data-gene expression data matrix For the normalization, the following two steps were taken. a) When measuring the density of the spots using Gene Spring software, the ratio of Cy 3 and Cy 5 dyes was adjusted as 1 as a globle normalization for the whole slide. b) For the gene expression analysis, the results (midian of the density of the pixel in one spot was used) were normalized by a LOWESS (locally weighed scatter smoother) software provided by the Center for Applied Genomics, so that the results can be compared among the experiments performed at different times. (20)Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.). c) The following rules were made to decide the genes that were significantly changed: 1) Eliminate the genes with high density (over than 2X of background) in the 3DNA capture probe experiments; 2) Eliminate the genes with density lower than 2X of background ( 21) Lee HM, Greeley GH Jr, Englander EW. Age-associated changes in gene expression patterns in the duodenum and colon of rats. Mech Ageing Dev. 2001 Apr 15;122(4):355-71.); 3) Eliminate the genes with change over than 1.5X in dye flip-over experiment; 4) Eliminate the genes with opposite results in one experiments between dye flip-over comparisons; 5) Only the genes significantly changed over 3 in 5 comparisons in 4 h perfusion experiment and over 2 in 4 comparisons in 20 min perfusion experiment were considered as reliable and biologically important. d) The final results discribed in this paper were presented as Means + SE and the frequency of gene changed in the HF-perfused intestine. About the image, raw, and normalized data, and other detailed parameters, please see the gene expression data tables derived from the experiments in the NCBI's GEO database. The design for the dye labeling in this experiments is as the follows: 1) 5 comparisons were conducted in the 4 h-perfused HG vs HF experiment, in which in 3 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 2) 4 comparisons were conducted in the 20 min-perfused HG vs HF experiment, in which in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 3) 3 dye flip-over experiments using 1 RNA sample extracted from HF-perfused intestine and 2 samples extracted from HG-perfused intestines were performed to eliminate the false positive results induced by the dye labeling technique or other unsolved problems. 4) 2 experiments only applying 3DNA fluorescent probe, which is connected to complementary capture sequence, were performed to eliminate the false positive genes that were low expressed in the tissue. The procedures for synthesizing the first strand cDNA, labeling the cDNA, hybridizaion, and detecting the signals were performed following the manufacturer's protocols. Keywords: other
2004-01-28 | GSE996 | GEO
Project description:During pregnancy and lactation in the rat the small intestine in general and the mucosal epithelium in particular gain weight. The specific activities of sucrase, lactate dehydrogenase and succinate-tetrazolium reductase remain constant and those of glucose 6-phosphate dehydrogenase and isocitrate dehydrogenase increase. There is no evidence that the reported decrease in absorption per unit area or weight of mucosal epithelium during pregnancy and lactation is due to decreases in enzyme activities within the epithelium. The pattern of enzyme change shows that the response of the gut to the stimuli of pregnancy and lactation must be a complex one, possibly involving increases in the specific activities of some enzymes.
| S-EPMC1161758 | biostudies-other
Project description:1. The degradation rates and half-lives of hexokinase, 6-phosphogluconate dehydrogenase, lactate dehydrogenase, pyruvate kinase, glucose 6-phosphate dehydrogenase, phosphoglycerate kinase and aldolase were calculated from measurements of the decline in activities of these enzymes in rat small intestine during starvation. 2. The half-lives of the enzymes are: hexokinase, 5.7h; 6-phosphogluconate dehydrogenase, 7.6h; glucose 6-phosphate dehydrogenase, 6.0h; pyruvate kinase, 8.9h; lactate dehydrogenase, 8.7h; phosphoglycerate kinase, 8.7h; aldolase, 5.1h. 3. The significance of the results is discussed with respect to the regulation of enzyme concentrations in response to changes in diet.
| S-EPMC1177640 | biostudies-other
Project description:The intestine is composed of an epithelial layer containing rapidly proliferating cells that mature into two regions, the small and the large intestine. Although previous studies have identified stem cells as the cell-of-origin for intestinal epithelial cells, no studies have directly compared stem cells derived from these anatomically distinct regions. Here, we examine intrinsic differences between primary epithelial cells isolated from human fetal small and large intestine, after in vitro expansion, using the Wnt agonist R-spondin 2. We utilized flow cytometry, fluorescence-activated cell sorting, gene expression analysis and a three-dimensional in vitro differentiation assay to characterize their stem cell properties. We identified stem cell markers that separate subpopulations of colony-forming cells in the small and large intestine and revealed important differences in differentiation, proliferation and disease pathways using gene expression analysis. Single cells from small and large intestine cultures formed organoids that reflect the distinct cellular hierarchy found in vivo and respond differently to identical exogenous cues. Our characterization identified numerous differences between small and large intestine epithelial stem cells suggesting possible connections to intestinal disease.
| S-EPMC4353627 | biostudies-literature
Project description:BackgroundEph receptor tyrosine kinases EphB2 and EphB3, and ephrin-B1 ligand play a critical role in regulating small intestinal epithelial cell migration. Although well studied in developing brain, the expression pattern of Ephs/ephrins has not been delineated in the developing small intestine.AimsTo examine the gene expression of all known members of Ephs/ephrins during development of mouse small intestine.MethodsWe examined the expression of 21 A- and B-Ephs/ephrins in mouse small intestine or the Caco-2 cell line using reverse-transcription polymerase chain reaction (RT-PCR), quantitative (q)RT-PCR, and immunohistochemical analyses. EphB2-expressing cells from isolated crypts were detected by immunofluorescence and fluorescence-activated cell sorting (FACS) analyses.ResultsWith the exception of EphA5, all family members were expressed throughout the intestine at all ages examined. Most were uniformly expressed. In contrast, levels of EphA4, EphA8, EphB4, and ephrin-B2 messenger RNA (mRNA) were highest during early fetal development and declined with age. At E15, EphB2 and EphB4 proteins were diffusely expressed in proliferating stratified intestinal epithelial cells. By E18, the proteins had become localized to cell membranes of columnar epithelial cells within intervillus regions, and later were expressed on epithelial cell membranes in adult crypts. EphB2-expressing cells can be specifically isolated from crypt cell fractions.ConclusionsThe current study represents the first analysis of Ephs/ephrins during intestinal development. The elevated expression of EphA4, EphA8, EphB4, and ephrin-B2 during the fetal period of intestinal morphogenesis suggests an important role in development. Continued intestinal expression of other family members implicates a role in differentiation.
| S-EPMC3947671 | biostudies-literature
Project description:1. Phosphatidylcholine synthesis in the foetal, newborn and adult small intestine of rats was studied by determination of cytidine diphosphocholine-1,2-diacylglycerocholine phosphotransferase (cholinephosphotransferase) and acyl-CoA-1-acyl-sn-glycerol-3-phosphocholine acyltransferase (lysophosphatidylcholine acyltransferase) activities and the incorporation of [1-14C]oleic acid into phosphatidylcholine. 2. Cholinephosphotransferase activity was low in foetal jejunum and ileum, increased 3-4 fold in the ileum by 6 days of age and by 12 days in the jejunum. Jejunal activity remained constant throughout weaning; ileal activity gradually decreased to values 25% of that of the jejunum. 3. Lysophosphatidylcholine acyltransferase activity was high in foetal jejunum and ileum, decreased 70% immediately after birth in the jejunum and increased to adult values by 12 days of age. Ileal activity decreased by 20% after birth, but decreased more rapidly at weaning to 30% of the activity in jejunum. 4. Initial rates and steady-state incorporation of [1-14C]oleic acid into phosphatidylcholine by jejunal rings of 10 day-old rats exceeded that observed in jejunal rings from adult rats by 2-4-fold. 5. In the postnatal jejunum, neither cholinephosphotransferase and lysophosphatidylcholine acyltransferase activities nor oleic acid incorporation were stimulated by cortisone administration in vivo.
| S-EPMC1161589 | biostudies-other
Project description:Experiment description 1. Experimental design 1) Authors, laboratory, and contact: Xue-Lin Cui1, Patricia Soteropoulos2, Peter Tolias2, Ronaldo P. Ferraris1: 1Dept. of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, NJ 07103-2714, 2Center for Applied Genomics, PHRI, 225 Warren Street Newark, NJ 07103-3506. Contact to Dr. Ronaldo P. Ferraris. 2) Type of the experiment: treated vs. untreated comparison. 3) Experimental factors: Twenty to twenty-two old SD rats were use in the experiment. The intestines of paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h or 20-min, respectively. 4) Totally 14 experiments were done. 5) A common reference was not used for all the hybridizations. 6) Quality control steps ( 14) Miller RA, Galecki A, Shmookler-Reis RJ. Interpretation, design, and analysis of gene array expression experiments. J Gerontol A Biol Sci Med Sci. 2001 Feb;56(2):B52-7. (15) Tseng GC, Oh MK, Rohlin L, Liao JC, Wong WH. Issues in cDNA microarray analysis: quality filtering, channel normalization, models of variations and assessment of gene effects. Nucleic Acids Res. 2001 Jun 15;29(12):2549-57. ( 16) Yang YH, Speed T. Design issues for cDNA microarray experiments. Nat Rev Genet. 2002 Aug;3(8):579-88. (17) Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.): a) In the 4 h perfusion experiment, the intestines of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h, respectively. Totally five replicates were conducted. The RNA samples were extracted from HF- and HG-perfused intestines (n=5 pairs) then labelled with Cy 5 (HF1, HF2, HF3, HF4, and HF5) and Cy 3 (HG1, HG2, HG3, HG4, and HG5), respectively. At the same time, one dye swap experiment, in which the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF1) and Cy 5 (HG1), respectively, was done and used in the data analysis. b) In the 20 min perfusion experiment, the intestines of of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 20-min, respectively. Totally four replicates were conducted. In two of the four-replicate experiments, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 5 (HF1a and HF3a) and Cy 3 (HG1a and HG3a), respectively. In the other two of the four-replicate experiments, the dye was swapped, that is, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF2a and HF4a) and Cy 5 (HG2a and HG4a), respectively. c) Three self-self experiments using different samples (HF1, HG1, and HF2) and one capture primer alone experiment were conducted to eliminate the false positive genes and aid to analyze the data. 7) The goal of the experiment: Fructose induced the expression of GLUT5 mRNA in the small intestinal epithelial cells. But it is not clear about the mechanisms involved in the phenomenal. In this experiment, we hypothesize: the expression of some genes must be changed after fructose perfusion for 4-h, these genes may regulate GLUT5 gene transcription; the expression of some genes must be changed even after 20-min fructose perfusion, these genes may trigger the GLUT5 gene expression as early response gene. Our goal in this study is to find out these potencial gene. 8) Links (URL), citations 2. Samples used, extract preparation, labeling and hybridization 1) Bio-source properties a) Sprague Dawley rats (NCBI taxonomy); b) The rat was anesthetized using urathene. The rat body was kept at 37 oC under light. c) Descriptors relevant to the particular sample: the jejunum of the 20-d old rat pups (unknown sex) was perused. 2) Biomaterial manipulations: the jejunum was in vivo perfused with 100 mM HF or HG for 4-h or 20-min. At the end of each experiment, the jejunum was immediately cut out and snap frozen in liqued nitrogen, and then stored the tissue in -80 oC freezer. 3) RNA isolation: A RNeasy Midi Kit (QIAGEN Inc., Valencia, CA) was used to extract total RNA from the jejunum. The brief procesure is described in the Total RNA Extraction for RT-PCR and Microarray above. 4) Sample assignment to slides for labeling and hybridization: S1: HF1(Cy 5) vs HG1 (Cy 3); S2: HF2 (Cy 5) vs HG2 (Cy 3); S3: HF3 (Cy 5) vs HG3 (Cy 3); S4: HF4 (Cy 5) vs HG4 (Cy 3); S5: HF5 (Cy 5) vs HG5 (Cy 3); S6: HF2 (Cy 3) vs HG2 (Cy 5); S7: HF1a (Cy 5) vs HG1a (Cy 3); S8: HF3a (Cy 5) vs HG3a (Cy 3); S9: HF2a (Cy 3) vs HG2a (Cy 5); S10: HF4a (Cy 3) vs HG4a (Cy 5); S11: HG1 (Cy 5) vs HG1 (Cy 3); S12: HG3 (Cy 5) vs HG3 (Cy 3); S13: HF3 (Cy 5) vs HF3 (Cy 3); S14: Cy 3 vs Cy 5 capture primer. 5) Labeling and hybridization procedures and parameters: The 3DNA Submicro Oligo Expression Array Detection Kit (Genisphere Inc., Hatfield, PA) was employed to synthesize and label the complimentary DNA (cDNA) with fluorescent dye: Cy3 or Cy5. The reason why this indirect labeling method was chosen is based on a previous study which demonstrated that the method was more sensitive and consistent than direct labeling method or other indirect techniques like aminoallyl labeling method and MICROMAX tyramide signal amplification labeling method. (18)Yu J, Othman MI, Farjo R, et al: Molecular Vision 2002; 8:130-137). In the primary experiments, three, four, and five g of total RNA were tested for labeling and hybridization conditions. In the official experiments, four g of total RNA isolated from each sample were used for labeling and hybridization, because the signal to noise ratio is high at this concentration. In addition, at this concentration, all most of the low expressed genes are detectable and the highly expressed genes are not fully saturated. The procedure was conducted following the manufacturer's protocol. Briefly, the first strand cDNA was synthesized using a specific poly T Cy3 RT primer or a specific poly T Cy5 RT primer in different tubes for paired samples. Combine the Cy3 and Cy5 reactions in one tube and precipitate the sample in ethanol. After briefly drying the pellet, resuspend the pellet with 40 l of hybridization buffer. Subsequently, apply the hybridization mixture onto the array slide and hybridize overnight at 55 oC in a humidified chamber. Following the hybridization, the slides were washed by placing them into 50 ml conical tubes containing 2 x SSC, 0.2% SDS for 15 min, 2 x SSC for 10 min, 0.2 x SSC for 10 min, and 95% ethanol for 1 min all at room temperature, except for the first wash, in which the temperature was 42 oC. After drying the slides, the Cy3 and Cy5 capture (connected to dye molecues) reagents mixed in hybridization buffer was pipeted onto the slides, and then hybridize at 65 oC for 3 h following slides wash as described above. 3. Measurement data and spesifications of data processing 1) Raw data description Slides were scanned for Cy3 and Cy5 fluorescence using an Axon GenePix4000 microarray reader (GenePix 4000A, Axon instruments, Foster City, CA) and quantitated using GenePix software. Scan parameters: Scan power: Cy 3 : Cy 5 = 100:100; Laser power: Cy 3 : Cy 5 = 1.15:1.76; Spatial resolution: ???; Pixel size: 10 or 100 ???; Pixel number: F pixels: 50-100; B pixels: 400-500 ???; PMT voltage: 600-750 for Cy 5 channel, 650-850 for Cy 3 channel. 2) Image analysis and quantitation For the image analysis, the density of the spots was detected using Gene Spring (Silicon Genetics, Redwood City, CA) software (GeniPix 4.0) (19) Axon Instruments Inc. (1999) GenePix 4000A User's Guide. Axon Instruments, Union City, CA). It is commercially available. Description of the algorithm and all the parameters used: R = red channel signal = F635; G = green channel signal = B 532; M = log2(R/G); A = 1/2xlog2(RxG); User-difined parameter f = 40%. For the complete image analysis out put of each image, see the NCBI's GEO database (www.ncbi.nlm.nih.gov/geo). 3) Normalized and summarized data-gene expression data matrix For the normalization, the following two steps were taken. a) When measuring the density of the spots using Gene Spring software, the ratio of Cy 3 and Cy 5 dyes was adjusted as 1 as a globle normalization for the whole slide. b) For the gene expression analysis, the results (midian of the density of the pixel in one spot was used) were normalized by a LOWESS (locally weighed scatter smoother) software provided by the Center for Applied Genomics, so that the results can be compared among the experiments performed at different times. (20)Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.). c) The following rules were made to decide the genes that were significantly changed: 1) Eliminate the genes with high density (over than 2X of background) in the 3DNA capture probe experiments; 2) Eliminate the genes with density lower than 2X of background ( 21) Lee HM, Greeley GH Jr, Englander EW. Age-associated changes in gene expression patterns in the duodenum and colon of rats. Mech Ageing Dev. 2001 Apr 15;122(4):355-71.); 3) Eliminate the genes with change over than 1.5X in dye flip-over experiment; 4) Eliminate the genes with opposite results in one experiments between dye flip-over comparisons; 5) Only the genes significantly changed over 3 in 5 comparisons in 4 h perfusion experiment and over 2 in 4 comparisons in 20 min perfusion experiment were considered as reliable and biologically important. d) The final results discribed in this paper were presented as Means + SE and the frequency of gene changed in the HF-perfused intestine. About the image, raw, and normalized data, and other detailed parameters, please see the gene expression data tables derived from the experiments in the NCBI's GEO database. The design for the dye labeling in this experiments is as the follows: 1) 5 comparisons were conducted in the 4 h-perfused HG vs HF experiment, in which in 3 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 2) 4 comparisons were conducted in the 20 min-perfused HG vs HF experiment, in which in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 3) 3 dye flip-over experiments using 1 RNA sample extracted from HF-perfused intestine and 2 samples extracted from HG-perfused intestines were performed to eliminate the false positive results induced by the dye labeling technique or other unsolved problems. 4) 2 experiments only applying 3DNA fluorescent probe, which is connected to complementary capture sequence, were performed to eliminate the false positive genes that were low expressed in the tissue. The procedures for synthesizing the first strand cDNA, labeling the cDNA, hybridizaion, and detecting the signals were performed following the manufacturer's protocols.
2010-06-09 | E-GEOD-996 | biostudies-arrayexpress
Project description:Although there is no shortage of potential drug targets, there are only a handful known low-molecular-weight inhibitors of protein-protein interactions (PPIs). One problem is that current efforts are dominated by low-yield high-throughput screening, whose rigid framework is not suitable for the diverse chemotypes present in PPIs. Here, we developed a novel pharmacophore-based interactive screening technology that builds on the role anchor residues, or deeply buried hot spots, have in PPIs, and redesigns these entry points with anchor-biased virtual multicomponent reactions, delivering tens of millions of readily synthesizable novel compounds. Application of this approach to the MDM2/p53 cancer target led to high hit rates, resulting in a large and diverse set of confirmed inhibitors, and co-crystal structures validate the designed compounds. Our unique open-access technology promises to expand chemical space and the exploration of the human interactome by leveraging in-house small-scale assays and user-friendly chemistry to rationally design ligands for PPIs with known structure.
| S-EPMC3299697 | biostudies-literature