Probe ordering and distancing by FISH.
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Cell Nucleus↗
Biomedical subjects
J Landegent
Publications and source records attributed to J Landegent.
Fluorescence in situ hybridization with human chromosome-specific libraries: detection of trisomy 21 and translocations of chromosome 4.
Chromosomes can be specifically stained in metaphase spreads and interphase nuclei by in situ hybridization with entire chromosome-specific DNA libraries. Unlabeled human genomic DNA is used to inhibit the hybridization of sequences in the library that bind to multiple chromosomes. The target chromosome can be made at least 20 times brighter per unit length than the others. Trisomy 21 and translocations involving chromosome 4 can be detected in metaphase spreads and interphase nuclei by using this technique.
Cells, Cultured↗
Detection of chromosome aberrations in the human interphase nucleus by visualization of specific target DNAs with radioactive and non-radioactive in situ hybridization techniques: diagnosis of trisomy 18 with probe L1.84.
The localization of chromosome 18 in human interphase nuclei is demonstrated by use of radioactive and non-radioactive in situ hybridization techniques with a DNA clone designated L1.84. This clone represents a distinct subpopulation of the repetitive human alphoid DNA family, located in the centric region of chromosome 18. Under stringent hybridization conditions hybridization of L1.84 is restricted to chromosome 18 and reflects the number of these chromosomes present in the nuclei, namely, two in normal diploid human cells and three in nuclei from cells with trisomy 18. Under conditions of low stringency, cross-hybridization with other subpopulations of the alphoid DNA family occurs in the centromeric regions of the whole chromosome complement, and numerous hybridization sites are detected over interphase nuclei. Detection of chromosome-specific target DNAs by non-radioactive in situ hybridization with appropriate DNA probes cloned from individual chromosomal subregions presents a rapid means of identifying directly numerical or even structural chromosome aberrations in the interphase nucleus. Present limitations and future applications of interphase cytogenetics are discussed.
Cell Nucleus↗
Detection of DNA sequences in nuclei in suspension by in situ hybridization and dual beam flow cytometry.
This report describes the fluorescence hybridization of DNA sequence probes to interphase nuclei in suspension and the quantification of bound probe by dual beam flow cytometry. Nuclear proteins were first cross-linked with dimethylsuberimidate to prevent disintegration of the nuclei during denaturation and hybridization. To demonstrate that in situ hybridization can be performed in suspension, stabilized mouse thymocyte nuclei were hybridized with a probe for mouse satellite DNA sequences. The DNA probes were labeled with 2-acetylaminofluorene. After hybridization, an indirect immunofluorescent labeling procedure was used to visualize the target sequences. With dual beam flow cytometry, both the amount of hybridized probe and the DNA content of individual nuclei were determined. Thus, the specificity of DNA hybridization can be combined with the speed and quantitative analysis provided by flow cytometry.
2-Acetylaminofluorene↗
Further evidence against random polyclonal antibody formation in mice with lupus-like graft-vs-host disease.
The pathologic symptoms in F1 mice with chronic graft-vs-host disease (GVHD) (GVH F1) strongly resemble those of systemic lupus erythematosus (SLE). Mice with SLE-like GVHD do not produce antibodies to a number of non-self and self antigens. This finding is inconsistent with the widely accepted view that the (auto)-antibody formation in SLE is polyclonal in the sense that B cells are triggered at random, i.e., irrespective of their specificity. In the present study, therefore, we performed a systematic study of the kinetics of total IgM- and IgG-secreting splenic B cells and tested their specificities. The total IgM-secreting B cell population was increased only in the first week after the initiation of SLE-like GVHD; it seemed to reflect a random, but self-limited, polyclonal B cell stimulation. In contrast, the total number of IgG-secreting cells in the GVH F1 mice was increased to a much higher extent than that of the IgM-secreting cells and remained increased. At no time during GVHD was there an increase in the number of plaque-forming cells (PFC) spontaneously secreting IgG antibodies to non-self antigens. The GVH reaction (GVHR) did, however, lead to the appearance of PFC that secreted IgG antibodies to DNA. Similarly, the GVH F1 mice showed high serum titers of antibodies to self antigens characteristic of SLE and to endogenous viruses, but during the entire observation period they failed to develop serum antibodies to non-self antigens and insulin. Hence, the enhanced production of Ig, especially that of IgG, that occurs in SLE-like GVHD is not a random process, because it requires the presence of antigen, or signal 1. The data support our hypothesis that only certain kinds of self antigen, such as DNA and cell membrane epitopes, can cross-link the Ig receptors on the corresponding B cells and thus provide an adequate signal 1. Given the increase in help, or signal 2, in chronic GVHD, only the B cell clones that simultaneously receive an adequate signal 1 seem to be driven into clonal proliferation and IgG secretion.
Animals↗