Accessibility of an epitope common to all histone H3 variants in folded and unfolded chromatin as studied by a monoclonal antibody

Rapid and effective western blotting of histones from acid-urea-Triton and sodium dodecyl sulfate polyacrylamide gels: two different approaches depending on the subsequent qualitative or quantitative analysis

An improved method for the electrophoretic transfer of histones from sodium dodecyl sulfate (SDS) and acetic acid-urea-Triton X-100 (AUT) polyacrylamide gels onto nitrocellulose membranes is described. In the case of SDS-gels, it was not essential to equilibrate them before transfer while for the AUT-gels, an equilibration step is essential to prevent the interference of Triton X-100 with the binding of histones to nitrocellulose. Transfer efficiency was different for different histone classes. Two procedures were developed: (1) one suitable for qualitative studies, and (ii) another for quantitative transfer.

Eukaryotic cell components that bind to chlamydial elementary bodies: the histones

HeLa-cell-membrane fractions isolated by sonication as used previously to identify chlamydial adhesins were examined by a blotting technique for binding chlamydial elementary bodies (EB). One HeLa cell protein with apparent molecular mass of 32 kDa was found to bind native EB. A monoclonal antibody (mAb) raised against this chlamydial binding host-cell protein reacted with eucaryotic histones. Histone fractions were capable of binding EB in an ELISA assay and histone H1 was identified as the chlamydial-binding host cell protein in the Hela cell membrane fraction. Probing with specific mAbs against histone H3 and DNA confirmed that chromatin components were present in the host-cell membrane extract. These data suggest that the HeLa-cell-binding chlamydial proteins were previously identified by their reaction with chromatin and not with membrane components.