Article Title: Specificity and binding kinetics of murine lupus anti-DNA monoclonal antibodies implicate different stimuli for their production
Figure Lengend Snippet: Model of apoptotic degradation of DNA initiated by CAD cleavage. The sequence of events starts with cleavage of condensed chromatin by activated CAD nuclease, followed by excision of 30–100 kilobase (kb) loops (with high GC content) and, after subsequent internucleosomal cleavage, formation of oligonucleosomal ladders of different sizes. Other fragments of loops, rich in AT, remain attached to the nuclear matrix and are released later. As the nuclear envelope collapses, various fragments of different sizes and composition are released and represent a source of potential autoantigens to drive autoimmune responses. It is known30 that different cell organelles or their fragments are released in apoptotic blebs, but smaller DNA fragments may escape this mode of elimination and are able to stimulate B cells for autoantibody production.
Article Snippet: Preparation of ds and ssDNA The dsDNA was prepared from calf thymus native DNA (Sigma-Aldrich, Poole, Dorset, UK) first by treatment with S1 nuclease (Sigma) to remove ssDNA and then by phenol–chloroform extraction to remove protein.