Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Somatic mutation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 865 records · Page 48Linked to original sources
PubMed1971

Rate of somatic mutation in immunoglobulin production by mouse myeloma cells.

Cultures of mouse myeloma cells which secrete both heavy (H) and light (L) immunoglobulin chains were cloned in soft agar. Variants that synthesized neither chain, or only light chains, were detected by overlaying the growing colonies with antiserum specific for the individual immunoglobulin chains. The rate of conversion of heavy plus light chain producers to light chain producers was 1.1 x 10(-3) per cell per generation, as determined by fluctuation analysis.

Animals↗
PubMed1995

A well-differentiated B-cell line is permissive for somatic mutation of a transfected immunoglobulin heavy-chain gene.

pSV2neo plasmids containing an IgM heavy-chain gene with nonsense mutations in either the variable (V) or the constant (C) region were transfected into four differentiated mouse plasma cell lines: S107 and the NSO fusion partner (myeloma cell lines) and 2C3 and 36.65 (hybridoma cell lines). The frequencies of reversion of the nonsense mutations in multiple independent transfectants were determined with the spot ELISA and rates of reversion were calculated by fluctuation analysis. Mutations in both V and C regions were confirmed by sequence analyses. In the S107 cell line, spontaneous point mutations occurred in the V region at a rate of approximately 5 x 10(-5)/bp per cell generation, > 400-fold higher than the rate of V-region mutation in the NSO cell line and considerably higher than the rates in 2C3 and 36.65 hybridoma cell lines. These studies suggest that S107 is a relatively permissive cell line in which V-region mutations can occur constitutively, even though it represents a late stage of B-cell differentiation. Further, the results show that the construct used contains sufficient information in its flanking and coding sequences to allow a relatively high rate of V-region mutation, at least in the S107 cell line.

Amino Acid Sequence↗
PubMed1997

Somatic mutations in the p53 tumor suppressor gene in rheumatoid arthritis synovium.

The factors that regulate the perpetuation and invasiveness of rheumatoid synovitis have been the subject of considerable inquiry, and the possibility that nonimmunologic defects can contribute to the disease has not been rigorously addressed. Using a mismatch detection system, we report that synovial tissue from the joints of severe chronic rheumatoid arthritis patients contain mutant p53 transcripts, which were not found in skin samples from the same patients or in joints of patients with osteoarthritis. Mutant p53 transcripts also were identified in synoviocytes cultured from rheumatoid joints. The predicted amino acid substitutions in p53 were identical or similar to those commonly observed in a variety of tumors and might influence growth and survival of rheumatoid synoviocytes. Thus, mutations in p53 and subsequent selection of the mutant cells may occur in the joints of patients as a consequence of inflammation and contribute to the pathogenesis of the disease.

Arthritis, Rheumatoid↗
PubMed1975

Maximum r.b.e. of fission neutrons for induction of somatic mutations in maize.

This investigation was conducted to determine the maximum r.b.e. of fission neutrons for the induction of yellow-green sectors in maize. Seeds heterozygous for the yg2 locus were adjusted to 13 per cent water content, irradiated with varying doses for eitherfission neutrons or 60Co gamma-radiation, and soaked for 2 hours in nitrogen-bubbled water at ambient temperature before planting. Frequency of yg2 sectors, as scored in leaves 4 and 5, increase linearly for both radiations. The r.b.e. values were greater than1100 at 0.40 sectors per leaf 4 and greater than 600 at 0.20 sectors per leaf 5; however, at these low frequencies, the standard errors were 3 times greater than the r.b.e. At 6.0 sectors per leaf 4, the r.b.e. values were 111 plus or minus 9; and at 3.0sectors per leaf 5, 118 plus or minus 21. As measured by sectors per krad, mutagenic efficiency increased with increased dose of gamma-radiation; the opposite was true for fission neutrons. This trend was more evident for leaf 4 than for leaf 5.

Cobalt Radioisotopes↗
PubMed1997

Somatic mutation in paroxysmal nocturnal hemoglobinuria.

The mutation, occurring in a hematopoietic stem cell, creates an erythrocyte clone deficient in proteins capable of blocking complement-mediated lysis. The precise defect lies, however, in the biosynthesis of anchors to tether the proteins. Future research may explain how the clone gains a growth advantage (perhaps shedding light on aplastic anemia). Meanwhile, there remains the challenge of optimal diagnosis and management.

Erythrocytes↗
PubMed2005

Genotoxicity testing of four textile dyes in two crosses of Drosophila using wing somatic mutation and recombination test.

In this study, four textile dyes, namely Astrazon Yellow, Red, Blue, and Black, were tested for their genotoxic effects in the wing cells of Drosophila melanogaster. Two crosses were used, the standard cross (ST) and the improved high-bioactivation cross (HB), the latter being characterized by increased sensitivity to the genotoxic effects of promutagens and procarcinogens. Three-day-old larvae were exposed to different concentrations of dyes. Commonly known mutagens were applied as positive controls. All concentrations of textile dyes, ethyl methanesulfonate (EMS), and urethane caused a decrease in survival proportional to concentration used. EMS and urethane caused an increase in the number of all types of spots in both standard and high-bioactivation crosses. Compared to ST crosses, the number of induced spots in the HB cross treated with urethane was considerably high. Treatment of the standard and the high-bioactivation crosses with textile dyes gave positive results, apparent from increase in the frequency of the small single spots. Yellow and red dyes also increased the number of large single spots in both crosses, whereas the twin spots were positive only at the highest dose of yellow dye. All these results indicate that D. melanogaster wing spot test can be recommended as a suitable in vivo test for the determination of genotoxicity of textile dyes.

Animals↗
PubMed1988

Autoantibody-associated kappa light chain variable region gene expressed in chronic lymphocytic leukemia with little or no somatic mutation. Implications for etiology and immunotherapy.

Recently the minor B cell subpopulation that expresses the CD5 (Leu-1) antigen has been implicated as a source of IgM autoantibodies. Chronic lymphocytic leukemia (CLL), the most common leukemia in humans, represents a malignancy of small B lymphocytes that also express the CD5 antigen. However, little is known concerning the antibody variable region genes (V genes) that are used by these malignant CD5 B cells. We have found that a relatively high frequency of CLL patients have leukemic B cells with surface immunoglobulin (sIg) recognized by 17.109, a murine mAb specific for a kappa light chain associated crossreactive idiotype (CRI) associated with rheumatoid factor and other IgM autoantibodies. Flow cytometric analyses revealed that the relative expression of the 17.109-CRI by circulating leukemic B cells was directly proportional to the levels of sIg kappa light chain, indicating that there exists stable idiotype expression in the leukemic population. To examine this at the molecular level, the nucleic acid sequences encoding the Ig kappa light chains of two unrelated patients with CLL bearing sIg with the 17.109-CRI were determined. Analyses of multiple independent kappa light chain cDNA clones did not reveal any evidence for sequence heterogeneity in the CLL cell population. Furthermore, the nucleic acid sequences expressed by the leukemic cells of these two patients were identical or very homologous to a germline V kappa gene isolated from placental DNA, designated Humkv 325, or "V kappa RF" because of its association with IgM autoantibodies. This study suggests; (a) that the malignant CD5+ B lymphocytes in CLL use the same V kappa gene that has been highly associated with IgM autoantibodies and (b) that the expression of V genes is stable in CLL, in contrast to other B cell malignancies examined to date. We propose that many CLL cases represent malignancies of autoreactive CD5 B cells that use a restricted set of conserved V genes. This property may render CLL particularly amenable to immunotherapy with antiidiotypic antibodies.

Amino Acid Sequence↗