Genome duplication in Leishmania major relies on persistent subtelomeric DNA replication
Jeziel D. Damasceno, Catarina A. Marques, Dario Beraldi, Kathryn Crouch, Craig Lapsley, Ricardo Obonaga, Luíz Ricardo Orsini Tosi, Richard McCulloch
Abstract
DNA replication is needed to duplicate a cell’s genome in S phase and segregate it during cell division. Previous work in Leishmania detected DNA replication initiation at just a single region in each chromosome, an organisation predicted to be insufficient for complete genome duplication within S phase. Here, we show that acetylated histone H3 (AcH3), base J and a kinetochore factor co-localise in each chromosome at only a single locus, which corresponds with previously mapped DNA replication initiation regions and is demarcated by localised G/T skew and G4 patterns. In addition, we describe previously undetected subtelomeric DNA replication in G2/M and G1-phase-enriched cells. Finally, we show that subtelomeric DNA replication, unlike chromosome-internal DNA replication, is sensitive to hydroxyurea and dependent on 9-1-1 activity. These findings indicate that Leishmania ’s genome duplication programme employs subtelomeric DNA replication initiation, possibly extending beyond S phase, to support predominantly chromosome-internal DNA replication initiation within S phase.