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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MOPC-315 (alpha lambda 2) is a BALB/c plasmacytoma that produces an anti-TNP antibody (M315). In addition to being secreted M315 is also expressed on the surface membranes of MOPC-315 cells. In the present studies an in vitro-adapted line of MOPC-315 was used to study the effect of affinity-purified, isologous anti-idiotypic antibodies (a-Id315) and idiotype-specific T cells on M315 expression. We observed that both monoclonal and polyclonal a-Id315 mediated a reversible clearance of surface membrane M315 but did not influence M315 secretion or MOPC-315 growth even when the myeloma cells were cultured in the continuous presence of a-Id315 for three weeks. Clearance of surface M315 was rapid, reversible, and a-Id315 dose-dependent. M315:a-Id315 complexes were shed from MOPC-315 cells in the form of microscopic membranous vesicles and a-Id315 was consumed in the process. Protein synthesis was required for re-expression of surface M315 only if a presynthesized internal pool of M315 had previously been depleted. In contrast, idiotype-specific T cells mediated specific inhibition of M315 secretion without influencing surface M315 expression. Although the anti-idiotypic antibodies and the anti-idiotypic T-cells are both directed to the surface membrane immunoglobulin on the cloned B cell, the anti-idiotypic antibodies regulate surface membrane expression of immunoglobulin while the anti-idiotypic T-cells regulate secretion of immunoglobulin. These observations support the view that in idiotype regulation, surface membrane immunoglobulin molecules function as a focusing device for regulatory effectors which actually determine the quality of the effect achieved.
Mol Immunol 1983 Sep
PMID:Anti-idiotypic regulation of IgA expression in myeloma cells. 660 15

Nucleoplasmic and non-histone chromatin proteins from two unrelated and four related mouse plasmacytoma cell lines have been analysed by biosynthetic labelling with [35S]-methionine followed by one- and two-dimensional polyacrylamide gel electrophoresis. We have attempted to find a relationship between the patterns of nuclear proteins and gene expression in mutant plasmacytoma cell lines. The majority of nuclear proteins are common to all of the cell lines studied as would be expected if the majority of nuclear proteins are concerned with functions common to all plasma cells. There are, however, both qualitative and quantitative differences in the nuclear protein patterns of mutant and parent cell lines which appear to correlate with differences in gene expression. The turnover of nuclear proteins in two of the cell lines, MOPC 315.40 (IgA producer) and MOPC 315.32 (lambda 2 chain producer) was studied using pulse-chase techniques.
Mol Immunol 1983 Aug
PMID:Nuclear proteins associated with gene expression in mouse plasmacytoma cell lines. 662 42

Eight murine lymphoid tumor cell lines have been examined for the presence of high-affinity insulin receptors. The eight cell lines included two Abelson murine leukemia virus-transformed pre-B cell lines, three plasmacytoma cell lines, and three spontaneous T-cell lymphomas from AKR mice. All of the cell lines in the B-cell series had high-affinity insulin binding sites. The apparent equilibrium association constant (Ka) for the high-affinity binding sites on these cells was 1.3-3.3 X 10(9) M-1. Two of the T-cell lymphomas had high-affinity receptor levels so low as to be undetectable in the whole cell binding assay under the conditions used for assaying the other cell lines, although in binding assays performed at very high cell densities, these two cell lines did appear to have a small number of high-affinity insulin binding sites. These results indicate that the growth stimulus provided by the tumor virus in neoplastic transformation of the AKR thymic lymphocytes differs from that provided by lectins in blast transformation of lymphocytes in that the neoplastic transforming event does not always result in the emergence of large numbers of high-affinity insulin receptors. In addition, the existence of cell lines such as the T-cell lymphomas that have nearly exclusively low-affinity binding sites suggests that the low-affinity sites may represent a distinct receptor that is not freely interconvertible with the high-affinity receptor.
Mol Cell Biochem 1982 Sep 17
PMID:Insulin receptors on cultured murine lymphoid tumor cell lines. 675 19

A wheat germ cell-free system was used for translation of kappa-chain IgG1 messenger RNA isolated from mouse plasmacytoma MOPC 21 cells polysomes. The system was optimised for a number of ingredients of the incubation mixture. Incorporation of labelled amino acids in polypeptides was shown as a function of K+, Mg2+, exogenous mRNA concentration and time, mRNA was purificated by two successive oligo (dT)-cellulose chromatographies and two successive sucrose gradient centrifugations or polyacrylamide gel electrophoresis. Different fractions of poly(A)-RNA stimulated protein synthesis 20--30-fold in a wheat germ cell-free system. Analysis of the translation product of 14 and 16S mRNA by SDS-polyacrylamide gel electrophoresis revealed polypeptide comigrating with the authentic L-chain IgG1 and specifically precipitating by an antiserum to mouse IgG and L-chain IgGl (MOPC 21). The 18 and 28S mRNA fractions directed the synthesis of polypeptides with molecular weight up to 50 000 dalton. Immunospecific translation product of the 18 and 28S mRNA contain both L- and H-chains.
Mol Biol (Mosk)
PMID:[Translation of MOPC 21 plasmacytoma cell mRNA in a cell-free wheat germ system]. 677 86

Surface membrane immunoglobulin from MOPC-315 plasmacytoma cells (smM315) was isolated by nonionic detergent lysis of radioiodinated cells and affinity chromatography on Dnp-aminohexyl-Sepharose 4B. Verification of the solubilized molecule as an integral membrane protein, distinct from secreted MOPC-315 IgA (M315) was accomplished by NaDodSO4-PAGE, charge-shift electrophoresis and molecular sieve gel filtration with NP-40 and deoxycholate. smM315 was compared to reduced and alkylated monomeric secreted immunoglobulins from MOPC-315, MOPC-460, and XRPC-25 by quantitative affinity chromatography (QAC) using two differently substituted Dnp-aminohexyl-Sepharose 4B resins. Unique patterns of cross-reactivity of all secreted myeloma proteins were independently established with a competitive hapten inhibition assay using 125I-Dnp26BSA as the precipitating probe. After derivation with dinitrobenzylsulfonate, Dnp-aminohexyl-Sepharose 4B was modified with succinic anhydride which, with the inclusion of 0.03% Doc in a PBS and 0.1% NP-40 buffer, prevented nonhapten specific protein-matrix interactions during QAC. Dissociation constants determined by QAC for three ligands, (dinitrophenyl-glycine, trinitrophenyl-amino-caproate and tetramethylrhodamine) were essentially the same for smM315 and M315. Both of the other nitrophenyl binding IgA myelomas had distinct and significant differences in dissociation constants. Thus, for a differentiated antibody secreting cell which has undergone a heavy chain class switch, such as MOPC-315, the cell surface immunoglobulin has an identical ligand binding active-site as the secreted immunoglobulin.
Mol Immunol 1983 Jan
PMID:Determination of dissociation constants and ligand specificity of detergent solubilized surface membrane immunoglobulin A from MOPC-315. 685 76

It was found that during hot phenol fractionation of plasmacytoma MOPC-21 cells, which produce immunoglobulins of gamma 1 chi-type, separation of nuclear and nucleolar RNAs, differing in kinetics of accumulation of radioactive precursors, distribution during gradient centrifugation procedures and in base composition, takes place. D-RNA 63 degrees and D-RNA 85 degrees, which possess similar characteristics with D-RNAs, discovered earlier in other cells were isolated. It was stated, the D-RNA 85 degrees is considerably enriched by 3'-terminal poly(A) sequences in comparison with D-RNA 63 degrees. During translation in cell-free protein synthesising system from Xenopus oocytes, these two fractions of hnRNA induced formation of immunospecific products. D-RNA 85 degrees stimulated synthesis of gamma 1 and chi chains more efficiently, that D-RNA 63 degrees. Polyadenylated and non-adenylated both D-RNAs stimulated synthesis gamma 1 and chi chains of immunoglobulin G1 during translation. This fact indicates the absence of significant differences in the informational content. These results give opportunity to propose the existence of two levels of processing pre-mRNA for immunoglobulin chains.
Mol Biol (Mosk)
PMID:[Isolation, characterization, and translation of heterogeneous nuclear RNA from plasmacytoma cells]. 730 Aug 26

Cultures of mouse plasmacytoma cells (MPC-11) grown within the range 6-23 x 10(5) cells/ml showed considerable variation in cell cycle distribution profiles and also differences with regard to relative amounts of microsomal subfractions. The variability of appearance of heavy rough (HR) and light rough (LR) microsomal subfractions was not merely due to differences in nutritional state of the culture. Cultures containing a high S/G2 + M cell cycld distribution ratio showed a high content of HR microsomal membranes; as the S/G2 + M ratio decreased, so too decreased the amount of HR material whilst the amount of LR microsomal membranes increased. The results indicate that there is a direct correlation between phase of cell cycle and both amount and relative distribution of rough microsomal membranes, the smooth fraction (S), however, remains relatively unchanged.
Mol Cell Biochem 1980 Feb 28
PMID:Correlation of the effect of feeding upon the cell cycle distribution profiles of MPC-11 cells with the relative appearance of [3H]-choline labeled material in microsomal subfractions and other cell fractions. 737 54

The NF-kappa B/Rel family of at least five transcription factor polypeptides is thought to function both as a developmental regulator in B cells and as a rapid response system in all cells. To examine this notion in more detail, we determined the protein contents of both the inducible and constitutive NF-kappa B/Rel activities in a pre-B-cell line, 70Z/3, and a mature B-cell line, WEHI 231. NF-kappa B p50/p65 is the major inducible nuclear complex after lipopolysaccharide or phorbol myristate acetate treatment of 70Z/3 cells. The constitutive and inducible complexes in WEHI 231 cells are mainly composed of p50 and Rel. The constitutive or induced activities are all sensitive to I kappa B-alpha, but this inhibitor is very short-lived in WEHI 231 cells, suggesting that the balance between synthesis and degradation of I kappa B-alpha determines whether a particular cell lineage has constitutive activity. A patterned expression of the NF-kappa B/Rel activator proteins emerges from an analysis of other B-lineage cell lines and splenic B cells: mainly p50 and p65 in pre-B (and non-B) cells, a predominance of Rel and p50 in mature B cells, and expression of p52 and RelB in plasmacytoma lines. This ordered pattern of regulators may reflect the requirement for expression of different genes during terminal B-cell differentiation because different combinations of NF-kappa B/Rel family members preferentially activate distinct kappa B sites in reporter constructs.
Mol Cell Biol 1994 Aug
PMID:Sequential induction of NF-kappa B/Rel family proteins during B-cell terminal differentiation. 803 13

Mouse plasmacytomas generally express higher levels of RNA transcripts from endogenous intracisternal A-particle (IAP) proviral elements than do lipopolysaccharide-stimulated normal lymphocytes. Lymphocytes express a limited and highly characteristic set of IAP elements (lymphocyte-specific [LS] elements). In this study, we examined whether LS elements are expressed at higher levels after transformation of the cells and/or whether new IAP elements are activated. The IAP elements expressed in plasmacytoma MPC11 were characterized by sequence analysis of 22 cDNA clones. The long terminal repeats (LTRs) of the tumor cDNAs proved to be highly related in sequence. None of the clones was of the LS cDNA type. The MPC11 LTRs were five- to sixfold more active than an LS cDNA LTR when tested for promoter activity by transfection into plasmacytoma cells. The LTRs of the tumor-derived cDNAs contained a canonical ATF core sequence (ATF-PC), while the LS cDNAs contained an altered sequence (ATF-LS). An ATF-PC oligonucleotide probe detected multiple IAP transcripts on Northern (RNA) blots of RNA from several plasmacytoma but gave no reaction with RNA from stimulated B lymphocytes. In contrast, an ATF-LS probe detected higher levels of RNA in lymphocyte than in tumor RNAs. Thus, expression of IAP elements in transformed B cells is selective for a different set of regulatory sequence variants than those expressed in normal B cells. Other oligonucleotide probes representing LS- and PC-specific sequence variants detected multiple common hypomethylated IAP proviral loci in three independently derived plasmacytomas. Overall, the results show that established plasmacytomas exhibit a characteristic pattern of IAP proviral hypomethylation and regulatory sequence selection.
Mol Cell Biol 1993 Dec
PMID:Selective expression of intracisternal A-particle genes in established mouse plasmacytomas. 779 68

Using an assay that measures the removal of UV-induced pyrimidine dimers in specific DNA sequences, we have found that the Pvt-1, immunoglobulin H-C alpha (IgH-C alpha), and IgL-kappa loci are poorly repaired in normal B lymphoblasts from plasmacytoma-susceptible BALB/cAnPt mice. Breaksites in these genes are associated with the chromosomal translocations that are found in > 95% of BALB/cAnPt plasmacytomas. In contrast to those from BALB/cAnPt mice, B lymphoblasts from plasmacytoma-resistant DBA/2N mice rapidly repair Pvt-1, IgH-C alpha, and IgL-kappa. Further, (BALB/cAnPt x DBA/2N)F1 hybrids, which are resistant to plasmacytoma development, carry an efficient (DBA/2N-like) repair phenotype. Analysis of allele-specific repair in the IgH-C alpha locus indicates that efficient repair is controlled by dominant, trans-acting factors. In the F1 heterozygotes, these factors promote efficient repair of BALB/cAnPt IgH-C alpha gene sequences. The same sequences are poorly repaired in the BALB/cAnPt parental strain. Analysis of the strand specificity of repair indicates that both strand-selective and nonselective forms of repair determine repair efficiency at the gene level in nonimmortalized murine B lymphoblasts.
Mol Cell Biol 1994 Feb
PMID:DNA repair defects associated with chromosomal translocation breaksite regions. 828 1


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