Supplementary Material for: Holocentric Chromosomes of <i>Luzula elegans</i> Are Characterized by a Longitudinal Centromere Groove, Chromosome Bending, and a Terminal Nucleolus Organizer Region

The structure of holocentric chromosomes was analyzed in mitotic cells of <i>Luzula elegans</i>. Light and scanning electron microscopy observations provided evidence for the existence of a longitudinal groove along each sister chromatid. The centromere-specific histone H3 variant, CENH3, colocalized with this groove and with microtubule attachment sites. The terminal chromosomal regions were CENH3-negative. During metaphase to anaphase transition, <i>L. elegans</i> chromosomes typically curved to a sickle-like shape, a process that is likely to be influenced by the pulling forces of microtubules along the holocentric axis towards the corresponding microtubule organizing regions. A single pair of 45S rDNA sites, situated distal to <i>Arabidopsis</i>-telomere repeats, was observed at the terminal region of one chromosome pair. We suggest that the 45S rDNA position in distal centromere-free regions could be required to ensure chromosome stability.