Leishmania major chromosomes are replicated from a single high-efficiency locus supplemented by thousands of lower efficiency initiation events
Summary: DNA replication initiates at genome sites termed origins. Previous origin mapping approaches in the populations of the protozoan parasite Leishmania major were discordant, suggesting either a single origin per chromosome or 200-fold more origins. To reconcile these data and fully understand...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-08-01
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| Series: | Cell Reports |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2211124725008654 |
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| Summary: | Summary: DNA replication initiates at genome sites termed origins. Previous origin mapping approaches in the populations of the protozoan parasite Leishmania major were discordant, suggesting either a single origin per chromosome or 200-fold more origins. To reconcile these data and fully understand DNA replication dynamics, we have applied DNAscent, an assay that detects patterns of 5-bromodeoxyuridine (BrdU) incorporation in individual long-read DNA molecules. We confirm the pre-eminence of a single locus of DNA replication initiation in each chromosome and reveal a much larger number of lower-efficiency DNA replication initiation events whose abundance is greater as chromosome size increases. Each initiation site is a region of high AT content, increased G-quadruplex levels, lowered chromatin occupancy, and reduced levels of nascent RNA. Finally, we show that all DNA replication initiation results in mutagenesis. This work reveals a bimodal strategy for DNA replication programming in Leishmania that drives replication timing and sequence variation. |
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| ISSN: | 2211-1247 |