Yeast-like mRNA capping apparatus in Giardia lamblia Journal Article
| Authors: | Hausmann, S.; Altura, M. A.; Witmer, M.; Singer, S. M.; Elmendorf, H. G.; Shuman, S. |
| Article Title: | Yeast-like mRNA capping apparatus in Giardia lamblia |
| Abstract: | A scheme of eukaryotic phylogeny has been suggested based on the structure and physical linkage of the RNA triphosphatase and RNA guanylyltransferase enzymes that catalyze mRNA cap formation. Here we show that the unicellular pathogen Giardia lamblia encodes an mRNA capping apparatus consisting of separate triphosphatase and guanylyltransferase components, which we characterize biochemically. We also show that native Giardia mRNAs have blocked 5′-ends and that 7-methylguanosine caps promote translation of transfected mRNAs in Giardia in vivo. The Giardia triphosphatase belongs to the tunnel family of metal-dependent phosphohydrolases that includes the RNA triphosphatases of fungi, microsporidia, and protozoa such as Plasmodium and Trypanosoma. The tunnel enzymes adopt a unique active-site fold and are structurally and mechanistically unrelated to the cysteine-phosphatase-type RNA triphosphatases found in metazoans and plants, which comprise part of a bifunctional triphosphatase-guanylyltransferase fusion protein. All available evidence now points to the separate tunnel-type triphosphatase and guanylyltransferase as the aboriginal state of the capping apparatus. We identify a putative tunnel-type triphosphatase and a separate guanylyltransferase encoded by the red alga Cyanidioschyzon merolae. These findings place fungi, protozoa, and red algae in a common lineage distinct from that of metazoa and plants. © 2005 by The American Society for Biochemistry and Molecular Biology, Inc. |
| Keywords: | controlled study; protein expression; pathogenesis; nonhuman; proteins; animals; models, biological; phosphatase; pathology; dose-response relationship, drug; rna triphosphatase; trypanosoma; acid anhydride hydrolases; transfection; time factors; evolution, molecular; rna; amino acid sequence; molecular sequence data; sequence homology, amino acid; messenger rna; guanosine; rna caps; rna, messenger; nucleotide sequence; recombinant proteins; protein biosynthesis; plasmids; protein structure, tertiary; yeast; catalysis; dna primers; enzyme kinetics; molecular biology; luciferases; guanosine triphosphate; phosphoric monoester hydrolases; centrifugation, density gradient; protozoa; fungus; protozoon; hydrogen-ion concentration; metals; electrophoresis, polyacrylamide gel; mrna capping; giardia lamblia; rna capping; nucleotidyltransferases; glycerol; transferase; fungal enzyme; plasmodium; metazoon; cations; 7 methylguanosine; microsporida; red alga; giardia lambia; rna guanylyltransferase; algae, red |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 280 |
| Issue: | 13 |
| ISSN: | 0021-9258 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Date Published: | 2005-04-01 |
| Start Page: | 12077 |
| End Page: | 12086 |
| Language: | English |
| DOI: | 10.1074/jbc.M412063200 |
| PUBMED: | 15556935 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 18" - "Export Date: 24 October 2012" - "CODEN: JBCHA" - "Molecular Sequence Numbers: GENBANK: EAA42388, EAA42847;" - "Source: Scopus" |
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