Issues

Cover picture: Confocal microscopy images of a wild-type C. elegans two-cell embryo (top left) and a lin5 mutant larva (bottom right). The embryo was immunostained to detect LIN-5 (green) and counterstained with propidium iodide to visualize DNA (red). LIN-5 can be seen at the centrosomes in both cells and at the kinetochore microtubules of the metaphase cell (to the right). Homozygous lin-5 null mutants complete embryogenesis, as a consequence of maternal lin-5 function, but fail to undergo postembryonic cell divisions. The mutant larva shown was allowed to develop until the mid L1 stage and shows only background levels of LIN-5 antibody staining (green). Ventral cord precursor cells entered mitosis and displayed the phosphorylated histone H3 epitope (red) at the same time as wildtype animals, however, chromosome congression, sister chromatid separation, and cytokinesis all fail. See related article in this issue by Lorson et al., 73-86