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Biomedical subjects

C Hession

Publications and source records attributed to C Hession.

30 records · Page 2Linked to original sources

Uromodulin (Tamm-Horsfall glycoprotein): a renal ligand for lymphokines.

The protein portion of the immunosuppressive glycoprotein uromodulin is identical to the Tamm-Horsfall urinary glycoprotein and is synthesized in the kidney. Evidence that the glycoproteins are the same is based on amino acid sequence identity, immunologic cross-reactivity, and tissue localization to the thick ascending limb of Henle's loop. Nucleic acid sequencing of clones for uromodulin isolated from a complementary DNA bank from human kidney predicts a protein 639 amino acids in length, including a 24--amino acid leader sequence and a cysteine-rich mature protein with eight potential glycosylation sites. Uromodulin and preparations of Tamm-Horsfall glycoprotein bind to recombinant murine interleukin-1 (rIL-1) and human rIL-1 alpha, rIL-1 beta, and recombinant tumor necrosis factor (rTNF). Uromodulin isolated from urine of pregnant women by lectin adherence is more immunosuppressive than material isolated by the original salt-precipitation protocol of Tamm and Horsfall. Immunohistologic studies demonstrate that rIL-1 and rTNF bind to the same area of the human kidney that binds to antiserum specific for uromodulin. Thus, uromodulin (Tamm-Horsfall glycoprotein) may function as a unique renal regulatory glycoprotein that specifically binds to and regulates the circulating activity of a number of potent cytokines, including IL-1 and TNF.

Amino Acid Sequence

Plasminogen activator inhibitor 2: regulation of gene transcription during phorbol ester-mediated differentiation of U-937 human histiocytic lymphoma cells.

We have isolated and sequenced two cDNA clones coding for plasminogen activator inhibitor 2 (PAI-2). The cDNA was used to study the regulation of PAI-2 gene transcription by the tumor-promoting phorbol ester phorbol 12-myristate 13-acetate in the human histiocytic lymphoma cell line U-937. The tumor promoter caused a transient, 50-fold increase of PAI-2 gene transcription.

Base Sequence

Two human 35 kd inhibitors of phospholipase A2 are related to substrates of pp60v-src and of the epidermal growth factor receptor/kinase.

We have purified two 35 kd phospholipase A2 inhibitors from human placenta, which we refer to as lipocortin I and II. Both proteins exhibit similar biochemical properties and occur in placenta at about 0.2% of the total protein. By peptide mapping, sequence, and immunological analyses, we show that lipocortin I and the 35 kd substrate for the EGF-receptor/kinase from A431 cells are the same protein. By similar criteria, we determine that lipocortin II is the human analogue of pp36, a major substrate for pp60src, which has been characterized in chicken embryo fibroblasts and in bovine brush border preparations. The amino acid sequences of lipocortin I and II that we deduced from cDNA clones share 50% homology, indicating that they probably evolved from a common gene.

Amino Acid Sequence

Isolation of the bovine and human genes for Müllerian inhibiting substance and expression of the human gene in animal cells.

We have isolated the bovine and human genes for Müllerian inhibiting substance (MIS), a testicular glycoprotein that causes regression of the Müllerian duct during development of the male embryo. The mRNA sequence of bovine MIS, determined from an analysis of cDNA and genomic clones, codes for a protein of 575 amino acids containing a 24 amino acid leader peptide. The human gene has five exons that code for a protein of 560 amino acids. A comparison of the bovine and human MIS proteins reveals a highly conserved C-terminal domain that shows marked homology with human transforming growth factor-beta and the beta chain of porcine inhibin. Animal cells transfected with the human gene secrete biologically active MIS, which causes regression of the rat Müllerian duct in vitro.

Amino Acid Sequence

Antifolate-resistant Chinese hamster cells. Evidence for dihydrofolate reductase gene amplification among independently derived sublines overproducing different dihydrofolate reductases.

Purification of a cDNA probe specific for dihydrofolate reductase mRNA has allowed the relative quantification of dihydrofolate reductase gene numbers and mRNA levels between a line of Chinese hamster lung fibroblasts sensitive to the antifolate drugs methotrexate and methasquin and sublines which by virtue of their overproduction of the target enzyme dihydrofolate reductase are cross-resistant to these site-specific inhibitors. Previous results have shown that resistant sublines could overproduce one of two molecular weight forms of dihydrofolate reductase, one parental-like (Mr = 21,000) and one nonparental-like (Mr = 20,000), each encoded by a different mRNA present in elevated amounts in resistant cells (Melera, P. W., Wolgemuth, D., Biedler, J. L., and Hession, C. (1980). J. Biol. Chem. 255, 319--322). The cDNA-RNA and cDNA-DNA hybridization experiments reported here confirm the elevated levels of dihydrofolate reductase-specific mRNA in resistant cells and show that the overproduction of either molecular weight form of dihydrofolate reductase is accompanied by amplification in dihydrofolate reductase gene number.

Animals

Antifolate-resistant chinese hamster cells. Evidence from independently derived sublines for the overproduction of two dihydrofolate reductases encoded by different mRNAs.

A comparison by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the proteins synthesized by antifolate-sensitive (DC-3F) and -resistant (DC-3F/A3 and DC-3F/MQ19) Chinese hamster lung fibroblast cells has shown that an apparent molecular weight difference exists between the dihydrofolate reductases overproduced by the resistant sublines. Translation in a rabbit reticulocyte lysate system of polysomal and cytoplasmic mRNAs from the three sublines has shown that the overproduction of dihydrofolate reductase by resistant cells is accompanied by increased levels of dihydrofolate reductase-specific mRNA and that the different molecular weight forms of dihydrofolate reductase are encoded by their respective mRNAs.

Animals

Identification of mRNA in the slime mold Physarum polycephalum.

Using a differential extraction procedure which had previously been shown to yield one nucleic acid fraction enriched in cytoplasmic RNA and another enriched in nuclear RNA, we have been able to isolate two polyadenylated RNA populations from microplasmodia of Physarum polycephalum. The poly(A)-containing RNA from the cytoplasmic-enriched fraction accounts for approximately 1.2% of the cytoplasmic nucleic acid, has a number-average nucleotide size of 1339+/- 39 nucleotides, and has been shown, in a protein-synthesizing system in vitro, to be capable of directing the synthesis of peptides which have also been shown to be synthesized in vivo by microplasmodia. The poly(A)-containing RNA from the nuclear-enriched fraction has a number-average nucleotide size of 1533 +/- 104 nucleotides and represents a mixture of cytoplasmic and nuclear adenylated RNA molecules. Based upon these observations, we have identified the polyadenylated RNA isolated from the fraction enriched in cytoplasmic nuclei acid as Physarum poly(A)-containing messenger RNA.

Cell Nucleus

Combinations of tetrahydrouridine and cytosine arabinoside in mouse tumors.

Thirteen experimental mouse neoplasms were tested by cytidine (CR)-deaminase and deoxycytidine (dCR)-kinase levels. Four neoplasms, Sarcoma T241, Adenocarcinoma E0771, Lewis lung carcinoma (LL), and Sarcoma 180 Japan (S180J), considered to have high deaminase and sufficient dCR-kinase activities, were tested in vivo for combination chemotherapy with cytosine arabinoside (ara-C) and the CR-deaminase inhibitor, tetrahydrouridine (THU). THU did not significantly improve the growth inhibition of ara-C in a wide range of combinations in T241, E0771, LL, and the solid form of S180J, but more than doubled the survival time of the S180J ascites-bearing animals. Toxicity in the form of weight loss and toxic deaths was observed in some but not all groups, especially at high dosages of ara-C and THU. Tissue distribution of [3H]-ara-C and [14C]-THU in T241-bearing mice revealed an accelerated clearance of ara-C-derived radioactivity under the influence of THU in the tumor and five host tissues, but not in the small intestines. With the exception of the small intestines, clearance of THU-derived radioactivity was faster in all tissues studied compared to the clearance of [3H]-ara-C-derived radioactivity. Intracellular CR-deaminase levels were inhibited significantly, ie, dose dependent, in tumor and host kidney after a single ip injection of THU to E0771--bearing mice. In the solid S180J, with or without simultaneous ip administration of THU, [3H]-ara-C was not converted to 5'-di- and tri-phosphates at all. In mice bearing the ascites form of S180J, [3H]-ara-C was extensively converted to ara-C 5'-di- and tri-phosphates. THU increased both overall ara-C-derived radioactivity and the relative amounts of ara-C 5'-di- and tri-phosphates.

Adenocarcinoma

Cloning and expression of human lipocortin, a phospholipase A2 inhibitor with potential anti-inflammatory activity.

The anti-inflammatory action of glucocorticoids has been attributed to the induction of a group of phospholipase A2 inhibitory proteins, collectively called lipocortin. These proteins are thought to control the biosynthesis of the potent mediators of inflammation, prostaglandins and leukotrienes, by inhibiting the release of their common precursor, arachidonic acid, a process that requires phospholipase A2 hydrolysis of phospholipids. Lipocortin-like proteins have been isolated from various cell types, including monocytes, neutrophils and renal medullary cell preparations. The predominant active form is a protein with an apparent relative molecular mass (Mr) of 40,000 (40K). These partially purified preparations of lipocortin mimic the effect of steroids, and mediate anti-inflammatory activity in various in vivo model systems. Using amino-acid sequence information obtained from purified rat lipocortin, we have now cloned human lipocortin complementary DNA and expressed the gene in Escherichia coli. Our studies confirm that lipocortin is a potent inhibitor of phospholipase A2 activity.

Amino Acid Sequence