Sequence coding for a sexual stage specific protein of<i>Plasmodium falciparum</i>

Bruce, Marian C.; Baker, David A.; Alano, Pietro; Rogers, Neil C.; Graves, Patricia M.; Targett, G.A.T.; Carter, R.

doi:10.1093/nar/18.16.4991-b

Cited by 7 publications

(4 citation statements)

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“…The mRNA transcript was much more abundant in the sexual stage than in the asexual erythrocytic stages. Probes corresponding to Pfs16, a sexual stage-specific gene (Bruce et a]., 1990), and calmodulin, a house-keeping gene (Robson and Jennings, 1991), were used as controls (Fig. 5, B and C).…”

Section: Properties Of the Predicted Pfmrk Proteinmentioning

confidence: 99%

Pfmrk, A MO15‐Related Protein Kinase from Plasmodium falciparum

Robson

Chen

et al. 1996

European Journal of Biochemistry

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Cyclin-dependent kinases (Cdks) play a central role in the regulation of the eukaryotic cell cycle. A novel gene encoding a Cdk-like protein, Pjmrk, has been isolated from the human malaria parasite Plasmodiumfnlciparurn. The gene has no introns and comprises an open reading frame encoding a protein of 324 amino acids with a predicted molecular mass of 38 kDa. Database searches revealed a striking similarity to the Cdk subfamily with the highest similarity to human M01S (Cdk7). The overall sequence of Pfmrk shares 62% similarity and 46% identity with human M015, in comparison to the 49-58% similarity and 34-43 % identity with other human Cdks. Pfmrk contains two unique inserts: one consisting of S amino acids just before the cyclin-binding motif and the other composed of 13 amino acids within the T-loop equivalent region. Southern blots of genomic DNA digests and chromosomal separations showed that Pjmrk is a single-copy gene conserved between several parasite strains and is located on chromosome 10. A 2500-nucleotide transcript of this gene is expressed predominantly in the sexual blood stages (gametocytes), suggesting that Pfmrk may be involved in sexual stage development.Keywords: Plasmodium fakiparum ; cyclin-dependent kinase; cell cycle ; mRNA expression ; chrornosome localization.Plasmodium falciparum is the causative agent of the most serious form of human malaria, which remains one of the most prevalent infectious diseases in the tropics and subtropics and affects over 100 million people, resulting in 1-2 million deaths/ year. l? falciparum has a complicated life cycle, occurring extracellularly in the invertebrate and intracellularly in the vertebrate hosts where it undergoes four cycles of development. Sporozoites, injected by a mosquito bite, rapidly enter liver cells and then develop into exo-erythrocytic forms. After a few days they divide into thousands of merozoites that specifically invade red blood cells. The growth of the asexual erythrocytic stages progresses from ring to trophozoite to schizont, culminating in cell division followed by synchronous rupture of the infected erythrocytes to release free merozoites, causing the clinical symptoms and mortality of malaria. Merozoites invade erythrocytes again, continuing the asexual blood cycle. A small number of ring forms develop into inale and female gametocytes, which areCorre.Tponderzce to J

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Section: Properties Of the Predicted Pfmrk Proteinmentioning

confidence: 99%

Pfmrk, A MO15‐Related Protein Kinase from Plasmodium falciparum

Robson

Chen

et al. 1996

European Journal of Biochemistry

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“…To evaluate the quality of the RNA, probes corresponding to Pji16, a sexual-stage-specific gene (Bruce et al, 1990) and calmodulin, a house-keeping gene (Robson, 1993), were used as controls (Fig. 7).…”

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confidence: 99%

Protein Phosphatase β, a Putative Type‐2A Protein Phosphatase from the Human Malaria Parasite Plasmodium Falciparum

Baker

1997

European Journal of Biochemistry

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Protein phosphatases play a critical role in the regulation of the eukaryotic cell cycle and signal transduction. A putative protein serinehhreonine phosphatase gene has been isolated from the human malaria parasite Plasmodium fulciparum. The gene has an unusual intron that contains four repeats of 32 nucleotides and displays a high degree of size polymorphism among different strains of P. fulciparum. The open reading frame reconstituted by removal of the intron encodes a protein of 466 amino acids with a predicted molecular mass of approximately 53.7 kDa. The encoded protein, termed protein phosphatase p (PP-p), is composed of two distinct domains. The C-terminal domain comprises 315 amino acids and exhibits a striking similarity to the catalytic subunits of the type-2A protein phosphatases. Database searches revealed that the catalytic domain has the highest similarity to Schizosaccharomyces pombe Ppal (58% identity and 73% similarity). However, it contains a hydrophilic insert consisting of five amino acids. The N-terminal domain comprises 15 1 amino acid residues and exhibits several striking features, including high levels of charged amino acids and asparagine, and multiple consensus phosphorylation sites for a number of protein kinases. An overall structural comparison of PP-P with other members of the protein phosphatase 2A group revealed that PP-/3 is more closely related to Saccharomyces cerevisiue PPH22. Southern blots of genomic DNA digests and chromosomal separations showed that PP-/!J is a single-copy gene and is located on chromosome 9. A 2800-nucleotide transcript of this gene is expressed specifically in the sexual erythrocytic stage (gametocytes). The results indicate that PP-p may be involved in sexual stage development.

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“…Recently, Pfs16, a protein first described as being expressed in gametocytes (Bruce et al, 1990;Moelans et al, 1991), the sexual stage of the parasite, was proposed as being expressed also on the sporozoite surface. Polyclonal antibodies raised against a peptide and a fusion protein of Pfs 16 recognized a band with an apparent molecular mass of 16 kDa and gave positive staining by immunofluorescence and immunoelectron microscopy on P. falciparum sporozoites (Moelans et al, 1991(Moelans et al, , 1995.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, we undertook to repeat the studies using monoclonal antibodies and polyclonal antibodies recognizing Pfsl6 (Baker et al, 1994;Bruce et al, 1990Bruce et al, , 1994.…”

Section: Introductionmentioning

confidence: 99%

Absence of sporozoite-neutralizing activity of antibodies recognizing thePlasmodium falciparumsexual stage antigen Pfs 16

et al. 1997

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Summary :Pfs16 was isolated independently by two groups of researchers either by screening cDNA and genomic expression libraries with monoclonal antibodies raised against purified gametocytes of Plasmodium falciparum, or by a substractive cloning strategy. Expression of this antigen has been found unambiguously in gametocytes by both teams but in sporozoites by only one group. Moreover, the latter group reported that antibodies raised against recombinant Pfs16 proteins could prevent sporozoite penetration into human hepatoma cells and human hepatocytes. In contrast we have found that monoclonal and polyclonal antibodies specifically recognizing Pfs16 in gametocytes do not react with sporozoites. Moreover, they were shown to have no inhibitory activity against P. falciparum sporozoite penetration in human hepatocytes.

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Sequence coding for a sexual stage specific protein ofPlasmodium falciparum

Cited by 7 publications

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Pfmrk, A MO15‐Related Protein Kinase from Plasmodium falciparum

Pfmrk, A MO15‐Related Protein Kinase from Plasmodium falciparum

Protein Phosphatase β, a Putative Type‐2A Protein Phosphatase from the Human Malaria Parasite Plasmodium Falciparum

Absence of sporozoite-neutralizing activity of antibodies recognizing thePlasmodium falciparumsexual stage antigen Pfs 16

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