title: RNA uridylyltransferases.
abstract: The terminal RNA uridylyltransferases (TUTases) catalyze transfer of UMP residues to the 3' hydroxyl group of RNA. These activities are widespread among eukaryotes and appear to be involved in a variety of RNA-processing pathways. Recent studies of RNA editing in trypanosomatids have provided the first insights into the biological functions of RNA uridylyltransferases, which had eluded biochemical identification despite 30-year-old evidence of such activities in mammals and plants. Comparative sequence analysis of trypanosomal TUTases and their homologs revealed by large-scale genomic projects demonstrates a significant level of biochemical and structural diversity between putative uridylyltransferases. The conserved catalytic domain has acquired additional protein modules and appears to have adapted to perform functionally distinct tasks of guided U-insertion into mRNA and constrained addition of an oligo[U] tail to guide RNAs. Here I discuss the current knowledge of this novel enzyme family and possible roles of RNA uridylylation in the regulation of gene expression.
authors.affiliation: Department of Microbiology and Molecular Genetics, B240-Medical Sciences I, University of California, Irvine, CA 92697, USA. ruslan@uci.edu
authors.forename: R
authors.initials: R
authors.lastname: Aphasizhev
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D012316:RNA Nucleotidyltransferases / Q000737:chemistry* / Q000378:metabolism*; D014345:Trypanosoma / Q000201:enzymology*; D014529:Uridine / Q000378:metabolism
chemical_list: D012316:RNA Nucleotidyltransferases; C031687:UTP-RNA uridylyltransferase; D014529:Uridine