Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1997-10-23
pubmed:abstractText
In eukaryotic cells, especially in yeast, several genes encoding tRNAs contain introns. These are removed from pre-tRNAs during the maturation process by a tRNA-specific splicing machinery that is located within the nucleus at the nuclear envelope. Before and after the intron removal, several nucleoside modifications are added in a stepwise manner, but most of them are introduced prior to intron removal. Some of these early nucleoside modifications are catalyzed by intron-dependent enzymes while most of the others are catalyzed in an intron-independent manner. In the present paper, we review all known cases where the nucleoside modifications were shown to depend strictly on the presence of an intron. These are pseudouridines at anticodon positions 34, 35 and 36 and 5-methylcytosine at position 34 of several eukaryotic tRNAs. One common property of the corresponding intron-dependent modifying enzymes is that their activities are essentially dependent on the local specific architecture of the pre-tRNA molecule that comprises the anticodon stem and loop prolonged by the intron domain. Thus introns clearly serve as internal (cis-type) RNAs that guide nucleoside modifications by providing transient target sites in tRNA for selected nuclear modifying enzymes. This situation may be similar to the recently discovered (trans-type) snoRNA-guided process of ribose methylations of ribosomal RNAs within the nucleolus of eukaryotic cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0300-9084
pubmed:author
pubmed:issnType
Print
pubmed:volume
79
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
293-302
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Intron-dependent enzymatic formation of modified nucleosides in eukaryotic tRNAs: a review.
pubmed:affiliation
CNRS, Laboratoire d'Enzymologie et de Biochimie Structurales, Gif-sur-Yvette, France.
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't