Centrosome amplification in p53-/- Clara cells Confocal micrographs of wild type and p53-/- Clara cell cultures immunoflourescently labelled with anti-pericentrin (green) and counterstained with propidium iodide (red). a) Single centrosomes were predominantly observed in wild type cells. b) In p53-/- cultures, more than two centrosomes and/or clusters of pericentrin-staining material were frequently observed in interphase, mitotic (anaphase), and multinucleated cells. Top left) Interphase Clara cells displaying clumps of pericentriolar material (thick arrows) and a single nuclei. Top right) Anaphase Clara cell with 3 centrosomes (thin arrows) forming a tripolar spindle. Bottom left) Binucleated Clara cell displaying 4 centrosomes (thin arrows) unevenly distributed between the two nuclei. Bottom right) Multinucleated Clara cell with 3 nuclei and 8 centrosomes (thin arrows). Panel c) exhibits the effects of p53 on centrosome number in 48-hour Clara cell cultures.