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Biomedical subjects

C J March

Publications and source records attributed to C J March.

At least 55 records · Page 3Linked to original sources
PubMed1989

A pre-aspartate-specific protease from human leukocytes that cleaves pro-interleukin-1 beta.

Interleukin-1 beta is a 17.4-kilodalton hormone derived from a 33-kilodalton inactive precursor produced by monocytes. We used the precursor as a substrate to detect proteolytic activities in peripheral blood mono-nuclear cell-conditioned medium that might be involved in interleukin-1 beta processing. We found that the conditioned medium, following passage through DEAE-Sephacel, generates a biologically active fragment from the precursor that runs slightly higher than the mature hormone in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The responsible activity behaved as a single protein in ion exchange chromatography. It was completely inhibited by metal ion chelators and not by inhibitors of serine, cysteine, or aspartate proteases, and it was dependent on both calcium (or magnesium) and zinc. The enzyme was not inhibited by three substrate-based metalloprotease inhibitors, phosphoramidon, benzyloxycarbonyl-Gly-Leu-NH2, and N-(2-carboxy-3-phenylpropionyl)-Leu. NH2-terminal sequence analysis showed that cleavage of the precursor occurred between a histidine and an aspartate residue, and digestion of synthetic peptides indicated that the protease is specific for pre-aspartate cleavages.

Amino Acid Sequence↗
PubMed1989

Cloning the interleukin 1 receptor from human T cells.

cDNA clones of the interleukin 1 (IL-1) receptor expressed in a human T-cell clone have been isolated by using a murine IL-1 receptor cDNA as a probe. The human and mouse receptors show a high degree of sequence conservation. Both are integral membrane proteins possessing a single membrane-spanning segment. Similar to the mouse receptor, the human IL-1 receptor contains a large cytoplasmic region and an extracellular, IL-1 binding portion composed of three immunoglobulin-like domains. When transfected into COS cells, the human IL-1 receptor cDNA clone leads to expression of two different affinity classes of receptors, with Ka values indistinguishable from those determined for IL-1 receptors in the original T-cell clone. An IL-1 receptor expressed in human dermal fibroblasts has also been cloned and sequenced and found to be identical to the IL-1 receptor expressed in T cells.

Amino Acid Sequence↗
PubMed1988

Human rhinovirus 3C protease: cloning and expression of an active form in Escherichia coli.

A cDNA encoding the viral protease from the 3C region of human rhinovirus type 14 was expressed in Escherichia coli through the use of a periplasmic secretion vector. The recombinant protease contained an eight amino acid N-terminal extension that enabled its detection by a specific antibody. It was expressed at a level of approximately 1 mg/L of E. coli culture. Biological activity of the protease was assessed in vitro by using a chemically synthesized peptide consisting of a consensus picornavirus protease cleavage site, Arg-Ala-Glu-Leu-Gln-Gly-Pro-Tyr-Asp-Glu. The peptide was cleaved by the recombinant protease at the Gln-Gly bond, generating the product peptides Arg-Ala-Glu-Leu-Gln and Gly-Pro-Tyr-Asp-Glu, which could be separated from the substrate peptide by reversed-phase HPLC. An in vitro assay for the rhinovirus 3C protease was developed by observing the rate of disappearance of the substrate peak from chromatograms of the supernatants of digestion mixtures.

Amino Acid Sequence↗
PubMed1988

cDNA expression cloning of the IL-1 receptor, a member of the immunoglobulin superfamily.

Interleukin-1 alpha and -1 beta (IL-1 alpha and IL-1 beta) are cytokines that participate in the regulation of immune responses, inflammatory reactions, and hematopoiesis. A direct expression strategy was used to clone the receptor for IL-1 from mouse T cells. The product of the cloned complementary DNA binds both IL-1 alpha and IL-1 beta in a manner indistinguishable from that of the native T cell IL-1 receptor. The extracellular, IL-1 binding portion of the receptor is 319 amino acids in length and is composed of three immunoglobulin-like domains. The cytoplasmic portion of the receptor is 217 amino acids long.

Amino Acid Sequence↗
PubMed1988

Generation of biologically active interleukin-1 beta by proteolytic cleavage of the inactive precursor.

Interleukin-1 beta (IL-1 beta) is derived from an inactive precursor by proteolytic cleavage. To study IL-1 beta processing, we expressed the precursor in Escherichia coli, partially purified it, and used it as a substrate for various potentially relevant protease preparations. The precursor alone was virtually inactive, but incubation with membranes from human monocytes or myeloid cell lines yielded a 500-fold increase in IL-1 bioactivity. Western blot analysis of the incubated material showed that the 31,000-Da precursor is broken down to three major products, ranging from 17,400 to about 19,000 Da. The most active of these products is the smallest one, and it co-migrates during electrophoresis with mature IL-1 beta. Four purified known proteases were also tested for their effect on precursor IL-1 beta, and none of these products co-migrated with the mature protein. Chymotrypsin and Staphylococcus aureus protease yielded slightly larger products, which were highly active. Elastase and trypsin yielded substantially larger products, and these had little IL-1 activity. The products of three of the known proteases were identified by NH2-terminal sequencing. These results show conclusively that proteolysis of precursor IL-1 beta generates biological activity and that the cleavage must occur close to the mature NH2 terminus.

Base Sequence↗
PubMed1988

Stimulation of B-cell progenitors by cloned murine interleukin-7.

The events involved in the commitment and development of lymphoid lineage cells are poorly understood. We have used a recently described long-term culture system to establish a bioassay that can detect a novel growth factor capable of stimulating the proliferation of lymphoid progenitors. Using direct expression in mammalian cells we have isolated a complementary DNA clone encoding this novel haematopoietic growth factor, designated interleukin-7.

Amino Acid Sequence↗
PubMed1988

B cell precursor growth-promoting activity. Purification and characterization of a growth factor active on lymphocyte precursors.

We have used a biological assay system we developed to biochemically purify a previously uncharacterized murine lymphopoietic growth factor designated lymphopoietin 1 (LP-1). This factor is capable of stimulating the proliferation and extended maintenance of precursor cells of the B lineage. A stromal cell line producing LP-1 was established after transfection of primary stromal cultures with a plasmid encoding the transforming genes of SV40. This factor was purified to a single 25-kD species from the culture supernatant of an adherent stromal cell line. This material acts on immature lymphocytes, it binds to specific receptors on cells, and is distinct from previously described hematopoietic factors. LP-1 has been purified some 10(7)-fold with an overall recovery of 35%. The purified protein exhibits a specific activity of approximately 4 X 10(6) U/micrograms of protein and is active at a half-maximal concentration of 10(-13) M.

Animals↗
PubMed1987

Expression, purification and characterization of recombinant murine granulocyte-macrophage colony-stimulating factor and bovine interleukin-2 from yeast.

Expression and secretion of two lymphokines, murine granulocyte-macrophage colony-stimulating factor (MuGM-CSF) and bovine interleukin-2 (BoIL-2), to levels of 50-60 mg per liter were achieved by placing these cDNAs in a Saccharomyces cerevisiae expression vector that utilized the yeast alcohol dehydrogenase-2 promoter and alpha-factor leader peptide. These lymphokines were purified to homogeneity by direct application of the crude yeast medium to reversed-phase high-performance liquid chromatography. Despite the fact that both lymphokines contain at least one N-glycosylation site and have identical N-terminal residues (Ala-Pro-Thr), recombinant (R) GM-CSF was found to be heterogeneously glycosylated by yeast while RBoIL-2 was secreted without glycosylation. Additionally, approximately 40% of the RGM-CSF was found to be proteolytically cleaved after the second amino acid residue, while RBoIL-2 was found to be intact.

Animals↗
PubMed1987

Expression and purification of native human granulocyte-macrophage colony-stimulating factor from an Escherichia coli secretion vector.

The human granulocyte-macrophage colony stimulating factor (GM-CSF) was expressed and purified from a high-level Escherichia coli secretion vector. A cDNA fragment encoding mature GM-CSF was fused with the aid of a synthetic oligonucleotide to the E. coli outer membrane signal peptide (ompA) of the secretion expression vector pIN-III-ompA3. The primary construction, designated pLB5001, is under transcriptional control of the tandem lipoprotein promoter (lppP) lactose promoter-operator (lacPO), and is regulated by the lactose repressor. Upon induction, a polypeptide of MW = 14,600 was produced which had GM-CSF activity in a human bone marrow colony assay. The linker sequence between the ompA signal peptide and the amino terminus of the mature GM-CSF was removed by oligonucleotide-directed site-specific mutagenesis to produce GM-CSF with an authentic amino terminus. The resulting construct, designated pLB5001-4, expressed authentic GM-CSF with a specific activity similar to that observed for the pLB5001 specified GM-CSF. Both versions of GM-CSF were associated with the membrane fraction after osmotic shock, and were purified to homogeneity by DEAE-Sephacel chromatography, followed by reversed-phase HPLC. Amino acid sequencing from the amino terminus of the purified GM-CSF established that the ompA signal peptide was cleaved at its normal processing site in both cases.

Amino Acid Sequence↗
PubMed1986

Human granulocyte-macrophage colony-stimulating factor purified from a Hodgkin's tumor cell line.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) was purified from 3 liters of serum-free conditioned medium of the Hodgkin's tumor cell line L428 KSA. The conditioned medium contained a high specific activity of 2.5 X 10(5) units of total colony-stimulating factor per mg protein. Colony-stimulating factor activity was determined by colony formation by human fetal liver cells or mouse bone marrow cells. The latter bioassay discriminated colony-stimulating factor 1, a subclass specific for monocyte/macrophage production, and G-CSF, specific for granulopoiesis, from GM-CSF. The starting material contained predominantly GM-CSF with CSF-1 and G-CSF constituting 10% and 12%, respectively, of the total activity. A seven-stage purification scheme was employed. The first stage involved concentration by batch chromatography on calcium phosphate gel. Subsequent stages involved gel filtration on Ultrogel AcA44, affinity chromatography on concanavalin A-Sepharose, batch chromatography on calcium phosphate gel and high-performance liquid chromatography on C1 reversed-phase (TSK TMS-250), gel permeation and C8 reversed-phase columns. The purified material showed a single disperse band, having an Mr of 30,000, by silver staining on sodium dodecyl sulfate polyacrylamide gel electrophoresis. An amino-terminal sequence of 20 amino acids was determined in a gas-phase sequencer with 500 ng of purified material. The sequence was identical to that predicted from the cDNA sequence. It was active on human fetal liver cells with half-maximum colony formation at 1 X 10(-12) M, but was not active on mouse bone narrow cells.

Amino Acid Sequence↗
PubMed1986

Purification to homogeneity of a human hematopoietic growth factor that stimulates the growth of a murine interleukin 3-dependent cell line.

A human lymphokine derived from the 5637 bladder carcinoma has been purified to homogeneity by using sequential reverse-phase high pressure liquid chromatography. A high recovery of biological activity is obtained by using this purification. The NH2-terminal amino acid sequence shows no homology to human interleukin 1 (IL 1), human IL 2, murine IL 3, or human granulocyte-macrophage colony-stimulating factor. The growth-promoting properties of the 5637-derived factor can be rapidly assayed by using the murine IL 3-dependent 32D c1-23 cell line. The amino acid sequence described is identical to that recently described for a human granulocyte colony-stimulating factor.

Animals↗
PubMed1985

Detection and characterization of high affinity plasma membrane receptors for human interleukin 1.

Interleukin 1 (IL-1) is a polypeptide hormone that acts as a central mediator of inflammation. Since IL-1 action is presumably mediated by specific cell surface receptor(s), we have characterized the binding of this hormone to cells. Purified human IL-1 was labeled to high specific activity with 125I, using Bolton-Hunter reagent. The labeled protein binds specifically to LBRM-33-1A5 (a murine T lymphoma line previously shown to produce IL-2 in response to phytohemagglutinin and IL-1) with an affinity of approximately 0.2-2 X 10(10)/M and, at saturation, to approximately 500 receptors per cell, on intact cells at 8 degrees C in the presence of sodium azide. The affinity of unmodified IL-1 for the murine plasma membrane receptor is 0.9-2 X 10(10)/M, as measured by the inhibition of 125I-IL-1 binding. The murine receptor specificity has been confirmed by demonstrating that, among a series of 12 polypeptide hormones, only IL-1 inhibits 125I-IL-1 binding to LBRM-33-1A5 cells. Treatment of surface-bound 125I-IL-1 with bivalent water-soluble crosslinkers identified a membrane polypeptide of Mr 79,500 to which IL-1 is crosslinked. A variety of cell types have been surveyed for the capacity to bind 125I-IL-1 specifically. The presence of specific binding correlates with the capacity of the cells tested to respond to IL-1. Our results indicate that the biological effects of the polypeptide hormone IL-1 are mediated by high affinity plasma membrane receptors. The identification of these receptors should provide valuable insight into the apparently diverse biological activities of IL-1.

Animals↗
PubMed1985

Human interleukin 1. Purification to homogeneity.

We have purified human interleukin 1 (IL-1) to homogeneity by a simplified procedure that results in excellent yields of pure material that retains a high level of biological activity. IL-1, secreted by human peripheral blood macrophages that have been stimulated with Staphylococcus aureus, was purified by ion exchange chromatography and affinity chromatography on Procion Red agarose. The pure protein has a specific activity of 3.2 X 10(8) U/mg in the thymocyte mitogenesis assay, and is pyrogenic. No molecular weight heterogeneity was observed, in contrast to findings for mouse IL-1 and earlier reports of human IL-1. Purified IL-1, as analyzed by two-dimensional electrophoresis/electrofocusing gels, exhibited a series of charged species with isoelectric points ranging from 6.0 to 4.9, all with a molecular weight of approximately 17,500. Amino acid analysis indicated an abundance of acidic residues, in agreement with the low isoelectric points. There is little or no cysteine in the molecule. No evidence was found for the presence of carbohydrate moieties. The overall yield for this procedure was approximately 31% of the activity contained in the initial culture supernatant.

Animals↗
PubMed1985

Generation of anti-peptide monoclonal antibodies which recognize mature CSF-2 alpha (IL 3) protein.

The colony-stimulating factor CSF-2 alpha (IL 3) has been purified to homogeneity, the protein sequenced, and the gene encoding this lymphokine cloned. Knowledge of the protein sequence permitted the synthesis of peptides corresponding to the amino terminus of the molecule. These peptides, after conjugation to palmitic acid, were used to immunize mice. Spleen cells from mice immunized with one of these peptides (CSF-2 alpha 1-14) were fused with the myeloma cell line NS-1. The fusion resulted in the isolation of two hybridoma cell lines, designated 6A5 and 4D4, that secreted antibodies that were specific for the immunizing peptide. The antibodies did not react with a closely related peptide CSF-2 alpha 7-16. The antibodies were capable, however, of recognized CSF-2 alpha protein as judged by the ability of the antibodies to remove CSF-2 alpha activity from culture medium of PHA-stimulated LBRM-33-5A4 cells, to immunoprecipitate radiolabeled CSF-2 alpha protein, and to detect CSF-2 alpha protein bound to nitrocellulose membranes.

Animals↗
PubMed1984

Lymphokine purification by reversed-phase high-performance liquid chromatography.

Reversed-phase high-performance liquid chromatography has been used to purify to homogeneity two different lymphokines. Human IL-2 was purified on a C8 reversed-phase column in pyridine-acetate-propanol followed by chromatography on a C18 reversed-phase column in trifluoroacetic acid-acetonitrile. Protein sequence analysis of in situ-generated cyanogen bromide peptides obtained from this preparation established the homogeneity of this material and confirmed the amino acid sequence predicted from the published DNA sequence. Murine CSF-2 alpha was purified on a C18 reversed-phase column in trifluoroacetic acid-acetonitrile followed by chromatography on the same column in pyridine-acetate-propanol. The final preparation yielded a single band on a sodium dodecyl sulfate-polyacrylamide gel with a molecular weight of 24,500.

Amino Acid Sequence↗
PubMed1984

Purification and chemical characterization of the receptor for interleukin 2 from activated human T lymphocytes and from a human T-cell lymphoma cell line.

The cell surface receptor for interleukin 2 plays a central role in the biology of this T-cell growth factor. A combination of affinity chromatography, high-performance liquid chromatography, and NH2-terminal protein sequencing was used to purify and chemically characterize the interleukin 2 receptor both from phytohemagglutinin-activated T cells and from the human T-cell lymphoma cell line HuT-102. The receptor isolated from HuT-102 cells was purified 16,000-fold to homogeneity as evidenced by (i) a final specific activity close to the theoretical specific activity of 18,182 fmol of receptor per microgram of protein, (ii) a single band on polyacrylamide gel electrophoresis with an Mr of 55,000, and (iii) a unique, unambiguous NH2-terminal protein sequence. The receptor purified from phytohemagglutinin-activated T lymphocytes had an Mr of 60,000 but it had the same NH2-terminal protein sequence.

Amino Acid Sequence↗
PubMed1982

Definition of 5' and 3' structural boundaries of the chromatin domain containing the ovalbumin multigene family.

Hen oviduct nuclei were subjected to pancreatic DNase I treatment under conditions known to preferentially degrade transcriptionally active genes (Weintraub, H., and Groudine, M. (1976) Science (Wash. D. C.) 93, 848-856). The ovalbumin gene, its structurally related genes, X and Y, and the spacer and flanking DNA were all found to exist in a DNase I-sensitive configuration. The DNase I-sensitive region was extended more than 20 kilobases beyond the 5' end of the X gene and approximately an equal distance beyond the 3' end of the ovalbumin gene before it became DNase I-resistant. The transition from a DNase I-sensitive to a -resistant conformation in oviduct chromatin occurred in a gradient fashion with 10 kilobases of DNA. Thus, ovalbumin and its related genes, X and Y, exist in a 100-kilobase DNase-sensitive domain in the oviduct tissue. In contrast, the entire domain was resistant to DNase I in spleen, liver, and erythrocyte nuclei. When the transcription of ovalbumin, X, and Y genes was eliminated by the withdrawal of hormone from estrogen-stimulated chicks, the entire domain remained in a DNase I-sensitive configuration. We conclude that DNase I-sensitive domains may provide the structural capability for gene expression and appear to be a result of the differentiation process since they are cell-specific and contain potentially expressible genes of that cell type. Repetitive sequences within this domain have been mapped and the possible relationship of these repetitive sequences to the DNase I-sensitive structure is discussed.

Animals↗