View in EDS

Enzymatic formation of queuosine and of glycosyl queuosine in yeast tRNAs microinjected into Xenopus laevis oocytes. The effect of the anticodon loop sequence

Saved in:
Bibliographic Details
Title: Enzymatic formation of queuosine and of glycosyl queuosine in yeast tRNAs microinjected into Xenopus laevis oocytes. The effect of the anticodon loop sequence
Authors: Haumont, Etienne, Droogmans, Louis, Grosjean, Henri
Source: European journal of biochemistry / FEBS, 168 (1
Publisher Information: Wiley, 1987.
Publication Year: 1987
Subject Terms: Nucleoside Q -- biosynthesis, 0301 basic medicine, RNA, Transfer, Amino Acid-Specific -- genetics, Guanosine -- analogs & derivatives, Amino Acid-Specific -- genetics, Saccharomyces cerevisiae, Saccharomyces cerevisiae -- genetics, Structure-Activity Relationship, Xenopus laevis, 03 medical and health sciences, Nucleotides -- metabolism, Anticodon, Nucleoside Q, Oocytes -- enzymology -- metabolism, Animals, Pentosyltransferases, Xenopus laevis -- metabolism, Pentosyltransferases -- metabolism, 0303 health sciences, Base Sequence, Guanosine, Nucleotides, Sciences bio-médicales et agricoles, RNA, Transfer, Amino Acid-Specific, Transfer, Oocytes, RNA, Anticodon -- physiology
Description: The eukaryotic tRNA-guanine transglycosylases (queuine insertases) catalyse an exchange of guanine for queuine in position 34, the wobble nucleoside, of tRNAs having a GUN anticodon where N (position 36) stands for A, U, C or G. In tRNAAsp (anticodon QUC) and tRNATyr (anticodon Q psi A) from certain eukaryotic cells, the nucleoside Q-34 is further hypermodified into a glycosylated derivative by tRNA-queuine glycosyltransferase. In order to gain insight into the influence of the nucleosides in position 36, 37 and 38 of an anticodon loop on the potential of a tRNA to become a substrate for the two modifying enzymes, we have constructed several variants of yeast tRNAs in which the normal anticodon has been replaced by one of the synthetic anticodons GUA, GUC, GUG or GUU. In yeast tRNAAsp, the nucleosides 37 (m1G) and 38(C) have also been replaced by an adenosine. These reconstructed chimerical tRNAs were microinjected into the cytoplasm of Xenopus laevis oocytes and tested for their ability to react with the oocyte maturation enzymes. Our results indicate that the nucleosides in positions 36, 37 and 38 influence the efficiencies of conversion of G-34 to Q-34 and of Q-34 to glycosyl Q-34; the importance of their effects are much more pronounced on the glycosylation of Q-34 than on the insertion of queuine. The effect of the nucleoside in position 37 is of particular importance in the case of yeast tRNAAsp: the replacement of the naturally occurring m1G-37 by an unmodified adenosine (as it is in X. laevis tRNAAsp), considerably increases the yield of the glycosylation reaction catalysed by the X. laevis tRNA-queuine glycosyltransferase.
Document Type: Article
File Description: 1 full-text file(s): application/pdf
Language: English
ISSN: 1432-1033
0014-2956
DOI: 10.1111/j.1432-1033.1987.tb13408.x
Access URL: https://pubmed.ncbi.nlm.nih.gov/3117541
http://europepmc.org/abstract/MED/3117541
https://difusion.ulb.ac.be/vufind/Record/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/60209/Details
https://www.ncbi.nlm.nih.gov/pubmed/3117541
https://febs.onlinelibrary.wiley.com/doi/full/10.1111/j.1432-1033.1987.tb13408.x
https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1987.tb13408.x
http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/60209
Rights: Wiley TDM
Accession Number: edsair.doi.dedup.....55ecd8b78d500c7de5b00508897daac9
Database: OpenAIRE
Description
Abstract:The eukaryotic tRNA-guanine transglycosylases (queuine insertases) catalyse an exchange of guanine for queuine in position 34, the wobble nucleoside, of tRNAs having a GUN anticodon where N (position 36) stands for A, U, C or G. In tRNAAsp (anticodon QUC) and tRNATyr (anticodon Q psi A) from certain eukaryotic cells, the nucleoside Q-34 is further hypermodified into a glycosylated derivative by tRNA-queuine glycosyltransferase. In order to gain insight into the influence of the nucleosides in position 36, 37 and 38 of an anticodon loop on the potential of a tRNA to become a substrate for the two modifying enzymes, we have constructed several variants of yeast tRNAs in which the normal anticodon has been replaced by one of the synthetic anticodons GUA, GUC, GUG or GUU. In yeast tRNAAsp, the nucleosides 37 (m1G) and 38(C) have also been replaced by an adenosine. These reconstructed chimerical tRNAs were microinjected into the cytoplasm of Xenopus laevis oocytes and tested for their ability to react with the oocyte maturation enzymes. Our results indicate that the nucleosides in positions 36, 37 and 38 influence the efficiencies of conversion of G-34 to Q-34 and of Q-34 to glycosyl Q-34; the importance of their effects are much more pronounced on the glycosylation of Q-34 than on the insertion of queuine. The effect of the nucleoside in position 37 is of particular importance in the case of yeast tRNAAsp: the replacement of the naturally occurring m1G-37 by an unmodified adenosine (as it is in X. laevis tRNAAsp), considerably increases the yield of the glycosylation reaction catalysed by the X. laevis tRNA-queuine glycosyltransferase.
ISSN:14321033
00142956
DOI:10.1111/j.1432-1033.1987.tb13408.x