Genome duplication in < i > Leishmania major < /i > relies on persistent subtelomeric DNA replication

DNA replication is needed to duplicate a cell's genome in S-phase and segregate it during cell division. Previous work inLeishmania 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 colocalise 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 thatLeishmania'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.
Source: eLife - Category: Biomedical Science Tags: Genetics and Genomics Microbiology and Infectious Disease Source Type: research