The Unique Structure of the Apicoplast Genome of the Rodent Malaria Parasite Plasmodium chabaudi chabaudi

Shigeharu Sato,Anthony A Holder,Abdul K Sesay,Georges Snounou

doi:10.1371/journal.pone.0061778

Shigeharu Sato, Anthony A Holder + Show 2 more

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https://doi.org/10.1371/journal.pone.0061778

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Abstract

The apicoplast, a non-photosynthetic plastid of apicomplexan species, has an extremely reduced but highly conserved genome. Here, the apicoplast genome of the rodent malaria parasite Plasmodium chabaudi chabaudi (Pcc) isolate CB was characterized. Although the set of genes in the genome is identical, the copy number of some tRNA genes differs between Pcc and other Plasmodium species because the Pcc DNA has only one rRNA/tRNA gene cluster, which is normally duplicated in other species. The location of the duplicated trnR(ACG) and trnM implies that one of the duplicated clusters in the ancestral molecule has been lost due to an intramolecular recombination event. The Pcc DNA occurs in two isoforms with an internal inversion between them. The presence of a unique variant in the duplicated trnT gene suggests that the two isoforms are interconvertible. This is the first report of the complete nucleotide sequence of a Plasmodium apicoplast DNA.

Highlights

The apicoplast is a secondary plastid of parasites belonging to the phylum Apicomplexa [1,2,3]
The results revealed that the gene repertoire, gene arrangement, and other structural attributes are strongly conserved in those species, except for a peculiarity in the plastid DNA of the rodent malaria parasite P. chabaudi chabaudi (Pcc) isolate AS
Variations located within trnT or in intergenic regions surrounding trnM were not unique at each position, implying that these parts are duplicated in the Plasmodium chabaudi chabaudi (Pcc) plastid DNA

Summary

Introduction

The apicoplast is a secondary plastid of parasites belonging to the phylum Apicomplexa [1,2,3]. It lacks photosynthetic activity, the organelle is critical for survival and growth [4]. The genes of two rRNAs (rrl and rrs) are arranged head-to-head and form a cluster with nine tRNA genes. The cluster is duplicated to form an inverted repeat (IR). Proteins encoded by this tiny genome are mostly involved in either transcription or translation and their genes comprise two unidirectional clusters in the single copy region following the trnT gene at one end of each IR unit

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