Molecular cloning and partial sequence of a 5.8 kilobase pair repetitive DNA from Plasmodium falciparum

Suplick, Kathleen; Akella, Rama; Saul, Allan; Vaidya, Akhil B.

doi:10.1016/0166-6851(88)90098-9

Cited by 42 publications

(18 citation statements)

References 5 publications

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“…This element is highly conserved across the genus Plasmodium and moderately conserved in other members of the phylum Apicomplexa. A nucleic acid fragment from P. yoelii with a structure similar to that of the P. gallinaceum element has been described previously (42,45). Preliminary sequence analysis has shown these entities to be about 80% similar (data not shown), supporting the argument that the element is highly conserved in other Plasmodium species.…”

Section: Discussionsupporting

confidence: 56%

Characterization of a conserved extrachromosomal element isolated from the avian malarial parasite Plasmodium gallinaceum.

Joseph¹,

Aldritt²,

Unnasch³

et al. 1989

Mol. Cell. Biol.

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We have identified a conserved, repeated, and highly transcribed DNA element from the avian malarial parasite Plasmodium gallinaceum. The element produced multiple transcripts in both zygotes and asexual blood stages of this parasite. It was found to be highly conserved in all of five malarial species tested and hybridized at reduced stringency to other members of the phylum Apicomplexa, including the genera Babesia, Eimeria, Toxoplasma, and Theileria. The copy number of the element was about 15, and it had a circularly permuted restriction map with a repeat unit length of about 6.2 kilobases. It could be separated from the main genomic DNA by using sucrose gradients and agarose gels, and it migrated separately from the recognized Plasmodium chromosomes on pulse-field gels. In the accompanying paper

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Section: Discussionsupporting

confidence: 56%

Characterization of a conserved extrachromosomal element isolated from the avian malarial parasite Plasmodium gallinaceum.

Joseph¹,

Aldritt²,

Unnasch³

et al. 1989

Mol. Cell. Biol.

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“…When this band was cloned and sequenced it was shown to be a human mitochondrial, rather than a plastid, rRNA gene. This is not especially surprising since it is well known that some regions of mitochondrial DNA have homologous regions within plastid DNA that can cause apparent cross-hybridization (Supplick et al, 1988). The failure to amplify apicoplast genes was not due to denatured gDNA since consistent amplification of a C. parvum-specific calcium transporter (Zhu & Keithly, 1997), which could not be amplified by PCR from a wide variety of organisms ( Fig.…”

Section: Analysis By Pcr Indicates That C Parvum Has No Plastid Genesmentioning

confidence: 95%

Cryptosporidium parvum appears to lack a plastid genome

2000

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Surprisingly, unlike most Apicomplexa, Cryptosporidium parvum appears to lack a plastid genome. Primers based upon the highly conserved plastid smallor large-subunit rRNA (SSU/LSU rRNA) and the tufA-tRNAPhe genes of other members of the phylum Apicomplexa failed to amplify products from intracellular stages of C. parvum, whereas products were obtained from the plastid-containing apicomplexans Eimeria bovis and Toxoplasma gondii, as well as the plants Allium stellatum and Spinacia oleracea. Dot-blot hybridization of sporozoite genomic DNA (gDNA) supported these PCR results. A T. gondii plastid-specific set of probes containing SSU/LSU rRNA and tufAtRNA Phe genes strongly hybridized to gDNA from a diverse group of plastidcontaining organisms including three Apicomplexa, two plants, and Euglena gracilis, but not to those without this organelle including C. parvum, three kinetoplastids, the yeast Saccharomyces cerevisiae, mammals and the eubacterium Escherichia coli. Since the origin of the plastid in other apicomplexans is postulated to be the result of a secondary symbiogenesis of either a red or a green alga, the most parsimonious explanation for its absence in C. parvum is that it has been secondarily lost. If confirmed, this would indicate an alternative evolutionary fate for this organelle in one member of the Apicomplexa. It also suggests that unlike the situation with other diseases caused by members of the Apicomplexa, drug development against cryptosporidiosis targeting a plastid genome or metabolic pathways associated with it may not be useful.

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“…These sequences have a bizarre organization, reminiscent of what has been observed in Chlamydomonas reinhardtii mitochondrial DNA (5). The rRNA-like regions of the 6.0-kb DNA show more than 95% conservation among the three diverse species of Plasmodium (P. yoelii, P. falciparum, and P. gallinaceum) from which we have sequence information (1,23,25; Morrisey and Vaidya, unpublished data). Hence, there appears to be evolutionary pressure to maintain the sequence and, by implication, the function of these fragmented rRNA domains.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, tandem arrays of the 6.0-kb sequence were detected in all tested species of * Corresponding author. malarial parasites (23,26), and no significant cross-hybridization could be observed between the 6.0-and 35-kb DNA molecules (M. J. Gardner, J. E. Feagin, and A. B. Vaidya, unpublished data).…”

mentioning

confidence: 99%

Complex transcription from the extrachromosomal DNA encoding mitochondrial functions of Plasmodium yoelii.

Suplick¹,

Morrisey²,

Vaidya³

1990

Mol. Cell. Biol.

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AU tested members of genus Plasmodium contain tandemly arrayed, transcribed, extrachromosomal DNA with a unit length of 6.0 kb. This DNA contains two open reading frames with potential to encode cytochrome c oxidase subunit I (coxl) and cytochrome b (cob) as well as fragments of rRNA genes scattered on both strands. At least 10 discrete RNA molecules transcribed during erythrocytic stages of a rodent malarial parasite, Plasmodium yoelii, were recognized by the 6.0-kb DNA probes. The RNA molecules of 1.4 and 1.1 kb were identified as encoding coxi and cob, respectively. Primer extension and RNA sequencing were used to locate and characterize 5' ends of these two RNAs, showing that an identical 12-nucleotide sequence, 5'-TATTTTT TGTTT-3', was present at these positions. This sequence may act as a promoter or as an RNA processing signal. A stem-loop structure signifying a possible transcription termination was present at the end of the coxi open reading frame. At least six discrete RNA molecules of less than 250 nucleotides were recognized by different fractions of the 6.0-kb DNA. The largest of these, 200 nucleotides, was also characterized by primer extension and RNA sequencing. This molecule had a high homology to portions of the large-subunit rRNA domains IV and V. Other, small RNA molecules were recognized by regions of the 6.0-kb DNA that had homology to the highly conserved peptidyltransferase domain of large-subunit rRNA. These results show that tlte unusual compactly organized mitochondrionlike DNA of malarial parasites is transcribed in a complex attern.Malarial parasites, members of genus Plasmodium, belong to phylum Apicomplexa of kingdom Protista. Organisms within this phylum include many important pathogens, such as species of the genera Toxoplasma, Babesia, and Eimeria, in addition to Plasmodium species, all of which are intracellular parasites. They possess a complex array of organelles, some of which may assist in invasion of host cells; others have unknown functions. Among the organelles of Plasmodium species are mitochondria, whose contributions to the parasite physiology are not entirely clear. Because mammalian Plasmodium species rely mainly on glycolysis for energy generation and lack many citric acid cycle enzymes (22), mitochondria have been thought to act primarily as electron sink for dihydro-orotate dehydrogenase during pyrimidine biosynthesis (17). And yet, observations with rhodamine 123 staining (11,24) and studies with mitochondrial inhibitors (4, 16) give a hint of organelles that may play a wider role in parasite biochemistry.Until recently, not much was known about the organelle DNA of malarial parasites. A circular DNA molecule of about 35 kb was observed by electron microscopy and assumed to be the mitochondrial genome (12,18,28). This assumption appeared to be substantiated when genes encoding rRNA sequences resembling those of procaryotes and mitochondria were found within the 35-kb circular DNA of Plasmodium falciparum (15). However, through DNA sequencing of a 6.0-kb tandemly...

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Molecular cloning and partial sequence of a 5.8 kilobase pair repetitive DNA from Plasmodium falciparum

Cited by 42 publications

References 5 publications

Characterization of a conserved extrachromosomal element isolated from the avian malarial parasite Plasmodium gallinaceum.

Characterization of a conserved extrachromosomal element isolated from the avian malarial parasite Plasmodium gallinaceum.

Cryptosporidium parvum appears to lack a plastid genome

Complex transcription from the extrachromosomal DNA encoding mitochondrial functions of Plasmodium yoelii.

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