Abstract
The Saccharomyces cerevisiae mRNA capping enzyme consists of two subunits: the RNA 5'-triphosphatase (Cet1) and the mRNA guanylyltransferase (Ceg1). Using computer homology searching, a S. cerevisiae gene was identified that encodes a protein resembling the C-terminal region of Cet1. Accordingly, we designated this gene CTL1 (capping enzyme RNAtriphosphatase-like 1). CTL1 is not essential for cell viability and no genetic or physical interactions with the capping enzyme genes were observed. The protein is found in both the nucleus and cytoplasm. Recombinant Ctl1 protein releases gamma-phosphate from the 5'-end of RNA to produce a diphosphate terminus. The enzyme is specific for polynucleotide RNA in the presence of magnesium, but becomes specific for nucleotide triphosphates in the presence of manganese. Ctl1 is the second member of the yeast RNA triphosphatase family, but is probably involved in an RNA processing event other than mRNA capping.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acid Anhydride Hydrolases / chemistry
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Acid Anhydride Hydrolases / genetics
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Acid Anhydride Hydrolases / metabolism*
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Amino Acid Sequence
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Base Sequence
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DNA Primers / genetics
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Fungal Proteins / chemistry
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Fungal Proteins / genetics
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Fungal Proteins / metabolism*
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Genes, Fungal
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Molecular Sequence Data
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Nucleotidyltransferases / chemistry
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Nucleotidyltransferases / genetics
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Nucleotidyltransferases / metabolism*
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Protein Conformation
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RNA Caps / metabolism
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RNA Processing, Post-Transcriptional
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Sequence Homology, Amino Acid
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Subcellular Fractions / enzymology
Substances
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DNA Primers
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Fungal Proteins
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RNA Caps
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Recombinant Fusion Proteins
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Nucleotidyltransferases
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mRNA guanylyltransferase
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Acid Anhydride Hydrolases
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RNA triphosphatase