scholarly journals Characterization of a binding protein for leukemia inhibitory factor localized in extracellular matrix

1993 ◽  
Vol 122 (3) ◽  
pp. 713-719 ◽  
Author(s):  
A Mereau ◽  
L Grey ◽  
C Piquet-Pellorce ◽  
JK Heath
Keyword(s):  
Extracellular Matrix ◽  
Binding Sites ◽  
Leukemia Inhibitory Factor ◽  
Protein A ◽  
Biologically Active ◽  
Inhibitory Factor ◽  
Stable Complex ◽  
Culture Dish ◽  
Chemical Cross Linking

Leukemia Inhibitory Factor (LIF) interacts with two classes of high affinity binding sites on rat UMR cells cultured in monolayer. One class of binding sites was found to be localized in the extracellular matrix (ECM) after removal of cells from the culture dish. The interaction of LIF with ECM-localized binding sites is not dependent upon either glycosylation of LIF or the presence of extracellular glycosyaminoglycans. Chemical cross-linking studies demonstrate that LIF interacts with a 200-kD cell-associated protein and a 140-kD ECM-localized protein. A 140-kD protein could also be specifically precipitated from solubilised metabolically radiolabeled UMR ECM by antibodies directed against LIF by virtue of its ability to form a stable complex with unlabeled LIF. In addition, soluble LIF associated with this ECM-localized protein is biologically active in terms of inhibition of ES cell differentiation. The properties of ECM-localized 140-kD species are very similar to those of the secreted form of the LIF receptor suggesting that the ECM localization of LIF and LIF signal transduction may be closely coupled.

STUDIES ON ACTH-BINDING ANTIBODIES: CHARACTERIZATION OF IMMUNOLOGICAL SPECIFICITIES

1969 ◽  
Vol 62 (3) ◽  
pp. 521-536 ◽  
Author(s):  
M. L. Aubert ◽  
J.-P. Felber
Keyword(s):  
Binding Sites ◽  
Competitive Inhibition ◽  
Biologically Active ◽  
Active Part ◽  
Terminal Portion ◽  
Plasma Acth ◽  
Acth Fragments ◽  
Selection Of

ABSTRACT In investigations on the production and the specificity of anti-ACTH antibodies used for radioimmunoassay, differences have been observed between the various antibodies obtained. It was shown by means of competitive inhibition with different ACTH fragments that the binding of the ACTH molecule to its antibody can occur at different sites along the ACTH peptide. By varying the concentrations of the fragments and the conditions of the assays, it was possible to study the properties of each antibody. Thus antibodies which bind the N-terminal portion, or which exclusively bind the biologically active part of the ACTH chain (1–20), are the most suitable for radioimmunoassay. It was found, however, that the production of antiserum was generally more frequent when binding occurred to the C-terminal portion of the ACTH peptide. Should the presence of such fragments in plasma be confirmed, then the use of these antisera could lead to erroneous measurement of biologically inactive ACTH fragments. Thus, this study reveals that a selection of the antibody for specificity might be necessary for its application to the radioimmunoassay of plasma ACTH, and that this selection could be performed with the use of ACTH fragments. An approach to the problem of binding sites between antigen and antibody has been described and the possibility of introducing a radioimmunoassay for plasma ACTH fragments discussed.

scholarly journals Characterization of NERF, a novel transcription factor related to the Ets factor ELF-1.

1996 ◽  
Vol 16 (9) ◽  
pp. 5091-5106 ◽  
Author(s):  
P Oettgen ◽  
Y Akbarali ◽  
J Boltax ◽  
J Best ◽  
C Kunsch ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Binding Sites ◽  
Fetal Liver ◽  
Protein A ◽  
Related Factor ◽  
Gene Promoters ◽  
Human Spleen ◽  
Related Transcription Factor ◽  
Ets Family

We have cloned the gene for a novel Ets-related transcription factor, new Ets-related factor (NERF), from human spleen, fetal liver, and brain. Comparison of the deduced amino acid sequence of NERF with those of other members of the Ets family reveals that the level of homology to ELF-1, which is involved in the regulation of several T- and B-cell-specific genes, is highest. Homologies are clustered in the putative DNA binding domain in the middle of the protein, a basic domain just upstream of this domain, and several shorter stretches of homology towards the amino terminus. The presence of two predominant NERF transcripts in various fetal and adult human tissues is due to at least three alternative splice products, NERF-1a, NERF-1b, and NERF-2, which differ in their amino termini and their expression in different tissues. Only NERF-2 and ELF-1, and not NERF-1a and NERF-1b, function as transcriptional activators of the lyn and blk gene promoters, although all isoforms of NERF bind with affinities similar to those of ELF-1 to a variety of Ets binding sites in, among others, the blk, lck, lyn, mb-1, and immunoglobulin H genes and are expressed at similar levels. Since NERF and ELF-1 are coexpressed in B and T cells, both might be involved in the regulation of the same genes.

Production and characterization of recombinant human leukemia inhibitory factor and evaluation of anti-fertility effects of rabbit anti-rhLIF in Balb/c mice

2020 ◽  
Vol 174 ◽  
pp. 105684
Author(s):  
Fateme Zare ◽  
Ali Akbar Saboor-Yaraghi ◽  
Hossein Hadinedoushan ◽  
Mahdi Dehghan-Manshadi ◽  
Farzaneh Mirzaei ◽  
...  
Keyword(s):  
Leukemia Inhibitory Factor ◽  
Inhibitory Factor ◽  
Human Leukemia
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