Biomaterial Database

Guanosine modifications in runoff transcripts of synthetic transfer RNA-Phe genes microinjected into Xenopus oocytes. 1990

H Grosjean, and L Droogmans, and R Giégé, and O C Uhlenbeck

Laboratoire de Biochimie, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France.

We have investigated whether unmodified yeast phenylalanine transfer RNA as well as one of its precursors containing an intron of nineteen nucleotides in the anticodon (pre-tRNA-Phe) can become substrates for selected tRNA modification enzymes present in a eukaryotic cell. This study was done by microinjecting into the cytoplasm of Xenopus laevis oocytes transcripts completely deprived of the naturally occurring modified nucleotides; these were obtained in vitro from appropriate synthetic genes under the control of bacteriophage T7 promoter. During the in vitro transcription, 32P labels were introduced with the guanosine triphosphate thus allowing easy detection of guanosine modifications in tRNA by two-dimensional chromatography after complete digestion into 5'-mononucleotides by nuclease P1. Results indicate that modifications occur on five guanosines (at positions 10, 26, 34, 37 and 46) in yeast tRNA-Phe and only on three guanosines (at 10, 26 and 46) in yeast precursor tRNA-Phe. These are the modifications expected from the known nucleotide sequences of naturally occurring Xenopus and yeast tRNA-Phe, i.e. N2-methyl-G10, N2,N2-dimethyl-G26, 2'-O-methyl-G34, N1-methyl-G37 or Y nucleoside-37 and N7-methyl-G46. The rates of modifications occurring in the two kinds of tRNA-Phe are faster in the intron-less tRNA-Phe than in the intron-containing tRNA-Phe. However quantitative modifications are only observed after as long as 75 h incubation in the oocytes.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008845	Microinjections	The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.	Microinjection
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D009865	Oocytes	Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).	Ovocytes,Oocyte,Ovocyte
D005260	Female		Females
D006151	Guanosine	A purine nucleoside that has guanine linked by its N9 nitrogen to the C1 carbon of ribose. It is a component of ribonucleic acid and its nucleotides play important roles in metabolism. (From Dorland, 28th ed)
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA