CELL SURFACE DNA - AN ANALYSIS OF SPECIFIC RECEPTORS

  • Bennett, Robert (Rob), (PI)

    Project: Research project

    Project Details

    Description

    The proposed study is based on the following observations from our previous
    work: (i) Certain peripheral white blood cells possess cell surface DNA
    (csDNA), based on the binding of a radioactive DNA probe - viz
    lactoferrin. (ii) When cells are stripped of their csDNA (by DNAse) they
    will take up exogenous DNA (3H labelled) in a saturable manner consistent
    with a ligand receptor relationship - for monocytes and neutrophils the Kd
    is about 2.5 x 10-billion M and some 1 to 2.5 x 1 million molecules of
    lambda phage DNA bind per cell. (iii) Using a biotin labelled DNA probe we
    have demonstrated a DNA binding protein in an SDS-PAGE preparation of
    neutrophil surface membranes; the MW of this putative DNA receptor was
    about 30,000. (iv) Preliminary studies of 3H DNA binding in normals and
    patients with connective tissue diseases indicates that some patients with
    systemic lupus erythematous (SLE) have an apparent DNA-receptor defect. It is intended to expand these findings as follows: (i) Establish which
    cell populations are capable of binding DNA; (ii) Verify that the binding
    is a saturable phenomenon with a Kd consistent with a ligand-receptor
    association; (iii) Determine whether bound DNA is internalized, and if so,
    if it is further degraded; (iv) Study factors influencing receptor turnover
    and regeneration; (v) Analyze purified membrane preparations from different
    cell types (using the biotin labelled DNA probe/PAGE system) for DNA
    binding proteins; (vi) Study the prevalence of deficient DNA binding in
    patients with SLE and see if this correlates with disease activity,
    serological markers inherited complement deficiencies or HLA typing; (vii)
    Look for abnormal DNA binding in other connective tissue disorders, other
    chronic diseases and normals; (viii) Try to determine whether deficient DNA
    binding is due to a receptor defect or a serum blocking factor. The definitive demonstration of a DNA receptor on certain immunocompetent
    cells would have important implications for molecular biology in general,
    and the confirmation of a receptor defect in SLE would open up a new avenue
    of research into the pathogenesis of this prototypical autoimmune disease.
    StatusFinished
    Effective start/end date9/20/858/31/88

    Funding

    • National Institutes of Health

    ASJC

    • Medicine(all)

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