The Replication of Plastid Minicircles Involves Rolling Circle Intermediates
Overview
Authors
Affiliations
Plastid genomes of peridinin-containing dinoflagellates are unique in that its genes are found on multiple circular DNA molecules known as 'minicircles' of approximately 2-3 kb in size, carrying from one to three genes. The non-coding regions (NCRs) of these minicircles share a conserved core region (250-500 bp) that are AT-rich and have several inverted or direct repeats. Southern blot analysis using an NCR probe, after resolving a dinoflagellate whole DNA extract in pulsed-field gel electrophoresis (PFGE), revealed additional positive bands (APBs) of 6-8 kb in size. APBs preferentially diminished from cells treated with the DNA-replication inhibitor aphidicolin, when compared with 2-3 kb minicircles, implicating they are not large minicircles. The APBs are also exonuclease III-sensitive, implicating the presence of linear DNA. These properties and the migration pattern of the APBs in a 2D-gel electrophoresis were in agreement with a rolling circle type of replication, rather than the bubble-forming type. Atomic force microscopy of 6-8 kb DNA separated by PFGE revealed DNA intermediates with rolling circle shapes. Accumulating data thus supports the involvement of rolling circle intermediates in the replication of the minicircles.
Dinochromosome Heterotermini with Telosomal Anchorages.
Kwok A, Yan K, Wen S, Sun S, Li C, Wong J Int J Mol Sci. 2024; 25(20).
PMID: 39457094 PMC: 11508785. DOI: 10.3390/ijms252011312.
DNA:RNA Hybrids Are Major Dinoflagellate Minicircle Molecular Types.
Kwok A, Leung S, Wong J Int J Mol Sci. 2023; 24(11).
PMID: 37298602 PMC: 10253752. DOI: 10.3390/ijms24119651.
Klinger C, Paoli L, Newby R, Wang M, Carroll H, Leblond J Genome Biol Evol. 2018; 10(4):1019-1038.
PMID: 29617800 PMC: 5888634. DOI: 10.1093/gbe/evy057.
Shinzato C, Mungpakdee S, Satoh N, Shoguchi E Front Microbiol. 2014; 5:336.
PMID: 25071748 PMC: 4083563. DOI: 10.3389/fmicb.2014.00336.
Massive gene transfer and extensive RNA editing of a symbiotic dinoflagellate plastid genome.
Mungpakdee S, Shinzato C, Takeuchi T, Kawashima T, Koyanagi R, Hisata K Genome Biol Evol. 2014; 6(6):1408-22.
PMID: 24881086 PMC: 4079212. DOI: 10.1093/gbe/evu109.