Biomaterial Database

Assembly of the U2 small nuclear ribonucleoprotein from Trypanosoma brucei. A mutational analysis. 1993

A Günzl, and M Cross, and Z Palfi, and A Bindereif

Max-Planck-Institut für Molekulare Genetik, Otto-Warburg-Laboratorium, Berlin, Federal Republic of Germany.

trans-Splicing in trypanosomes requires the functions of U2 and U4/U6 small nuclear (sn) RNPs. We have analyzed protein binding and assembly of the Trypanosoma brucei U2 snRNP, using specific antibodies against U2 snRNP proteins and in vitro reconstitution assays of U2 deletion derivatives and human-trypanosome hybrid RNAs. Stable binding of both the U2-specific 40-kDa and the common proteins requires only the 3'-terminal domain (stem-loop IIb, single-stranded region, and stem-loop IV), with loop IV providing the critical sequence determinant; stem-loop IV suffices for binding of the 40 kDa-protein, but not of the common proteins; surprisingly, the sequence of the "Sm-analogous" single-stranded region between stem-loops IIb and IV is not essential for protein binding. Our mutational analysis further indicates that interactions between common and specific proteins play an important role in the assembly of a stable core complex. Finally, a partially assembled U2 RNP complex could be identified as a kinetic intermediate of U2 snRNP assembly. We propose a model of the domain structure and assembly of the trans-spliceosomal U2 snRNP, which deviates in several aspects from that of the cis-spliceosomal U2 snRNP; these differences may be related to the trans-splicing-specific functions of the trypanosomal U2 snRNP.

UI	MeSH Term	Description	Entries
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
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
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
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
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
D014346	Trypanosoma brucei brucei	A hemoflagellate subspecies of parasitic protozoa that causes nagana in domestic and game animals in Africa. It apparently does not infect humans. It is transmitted by bites of tsetse flies (Glossina).	Trypanosoma brucei,Trypanosoma brucei bruceus,Trypanosoma bruceus,brucei brucei, Trypanosoma,brucei, Trypanosoma brucei,bruceus, Trypanosoma,bruceus, Trypanosoma brucei
D016053	RNA, Protozoan	Ribonucleic acid in protozoa having regulatory and catalytic roles as well as involvement in protein synthesis.	Protozoan RNA
D016054	DNA, Protozoan	Deoxyribonucleic acid that makes up the genetic material of protozoa.	Protozoan DNA
D017413	Ribonucleoprotein, U2 Small Nuclear	A nuclear RNA-protein complex that plays a role in RNA processing. In the nucleoplasm, the U2 snRNP along with other small nuclear ribonucleoproteins (U1, U4-U6, and U5) assemble into SPLICEOSOMES that remove introns from pre-mRNA by splicing. The U2 snRNA forms base pairs with conserved sequence motifs at the branch point, which associates with a heat- and RNAase-sensitive factor in an early step of splicing.	Small Nuclear Ribonucleoproteins, U2,U2 Small Nuclear Ribonucleoproteins,U2 snRNP,Ribonucleoproteins, Small, U2