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U Storb

Publications and source records attributed to U Storb.

At least 91 records · Page 5Linked to original sources
PubMed1978

Immunoglobulin genes in DNA restriction fragments.

We have investigated the organization of immunoglobulin genes in mice. High molecular weight DNA from myelomas and Krebs ascites cells was cleaved with EcoRI restriction endonuclease and fractionated using preparative agarose gel electrophoresis. Each fraction was then hybridized to an immunoglobulin mRNA or a cDNA transcribed from the mRNA. In two series of experiments, one with a kappa chain probe (MOPC 41 mRNA), the other with a lambda chain probe (SAPC 178 mRNA), we analyzed a variety of myeloma DNAs and Krebs DNA. In contrast to previously reported findings (Tonegawa, S., et al. (1976) Cold Spring Harbor Symp. Quant. Biol. 41, 877), we did not observe any unique restriction map pattern in the DNA from cells which exress a given immunoglobulin gene. We also found that restriction fragments containing c region genes do not appear to transpose, while DNA sequences corresponding to other portions of the kappa and lambda mRNAs do in some cases.

Animals↗
PubMed1978

Direct demonstration of immunoglobulin kappa chain RNA in thymus T cells by in situ hybridization.

Mouse thymuses with more than 99% T cells have been reported to contain immunoglobulin kappa mRNA-like molecules (kappa RNA) in relatively large quantities. The present study was undertaken to rule out the possibility that the kappa RNA was mainly a product of a few contaminating B cells of the thymus and to determine whether all T-cell subpopulations contained kappa RNA. By in situ hybridization with DNA complementary to kappa mRNA (kappa cDNA) the following observations were made: 98.5% of thymus cell preparations hybridized with kappa cDNA; the 1.5% unlabeled cells were generally larger and paler staining than the majority of thymus cells. Only 0.015% of thymus cells were intensely labeled and appeared to be plasma cells. Also, 87% of spleen cells hybridized with kappa cDNA; most of these showed similar labeling intensity to the majority of thymus cells. The number of unlabeled cells corresponded to the percentage of hemopoietic cells and macrophages in the spleen. Spleen cells in the range of 0.37-0.85% were intensely labeled and appeared to be plasma cells. The following controls supported the conclusion that the results with thymus and spleen were due to specific hybridization: most of the kappa mRNA-deficient tissue culture cells of the plasmocytoid tumor ABPL-4 did not hybridize with kappa cDNA. The kappa mRNA-producing cells from myeloma PC 3741 hybridized in situ with kappa cDNA. Furthermore, all cells from this tumor and all spleen cells hybridized uniformly with a cDNA probe complementary to most of the total cellular poly(A)-containing RNA species of these cells. These results indicate that T cells of all types in the thymus as well as in the periphery contain substantial quantities of kappa RNA.

Animals↗
PubMed1976

Sequences related to immunoglobulin kappa chain messenger RNA in T cells.

We investigated by molecular hybridization whether T cells contain RNA sequences homologous to RNA which codes for immunoglobulin kappa-chain (k-chain). A radioactive probe of complementary DNA (cDNA) was prepared by transcription of purified k-chain mRNA from mouse myeloma MOPC-41 with reverse transcriptase (RNA-dependent-DNA nucleotidyltransferase) from avian myeloblastosis virus. The cDNA probably corresponded only to the constant region and 3'-terminus of k-chain mRNA. Kappa-chain cDNA was found to hybridize efficiently with RNA from both thymus cells and an established culture of thymoma cells. The thymus and thymoma cells contained 99.8% and 100% theta-positive cells, respectively. Quantitatively the average thymus T cell (thymus derived lymphocyte) contained about one half as much k-chain mRNA as the average spleen B cell ("bursa" dependent lymphocyte), whereas the thymoma cells contained only 1/33 as much. Control hybridizations of k-chain cDNA with myeloma and liver RNA support the conclusion that T cells in the thymus and in the thymoma cell line synthesize k-chain mRNA-like molecules. The thermal stability of hybrids of k-chain cDNA with RNA from spleen, thymus, thymoma, and another k-chain producing myeloma tumor was lower than that with MOPC-41 RNA. This finding may be due to the existence of several slightly different ck genes in the mouse as suggested by various control experiments.

B-Lymphocytes↗
PubMed1976

Analysis of immunoglobulin genes: DNA/RNA hybridization with immunoglobulin kappa-chain mRNA and isolation and translation of hybridized RNA.

Immunoglobulin kappa-chain mRNA was hybridized with DNA in order to assess the kappa-gene frequency. Kappa-mRNA was purified from membrane-bound ribosomes of mouse myeloma MOPC-41 by poly (U) chromatography and isolation of a 13S RNA by successive sucrose density gradient centrifugations. The RNA coded for kappa-chain precursor molecules in cell-free protein synthesis and essentially no other proteins. MOPC-41 kappa-mRNA hybridized with MOPC-41, MPC-11, and Krebs DNA with the same kinetics: the majority of the hybrids was formed with rare or unique DNA sequences (Cot/2 450 to 900), a small portion with highly repetitive sequences (Cot/2 5--6). The slow hybrids were well matched and the rapid hybrids were mismatched by about 4%, regardless of the DNA used. It was further investigated whether the rapid hybrids contained translatable kappa-mRNA or were due to impurities in the RNA preparations. Kappa-mRNA and globin-mRNA (as an internal standard for a unique transcript) were hybridized with DNA to Cot 20 or 48, the hybridized and unhybridized RNA were isolated by hydroxyopatite-urea chromatography and, after removal of the DNA, translated in a cell-free system. The cell-free products were analyzed by SDS-polyacrylamide gel electrophoresis and immunoprecipitation. It was found that approximately equal quantities of translatable kappa- and globin-mRNA were hybridized maximally 1.7%). The results do not support the hypothesis that kappa-mRNA is a transcript of both repetitive and unique DNA sequences.

Animals↗