Biomaterial Database

Multiple factors including the small nuclear ribonucleoproteins U1 and U2 are necessary for pre-mRNA splicing in vitro. 1985

A R Krainer, and T Maniatis

We have identified six distinct factors necessary for pre-mRNA splicing in vitro by selective inactivation and complementation studies, and by fractionation procedures. Splicing factor 1 (SF1) is sensitive to micrococcal nuclease, and appears to consist of at least U1 and U2 snRNPs, since splicing is inhibited when the 5' termini of U1 and U2 snRNAs are removed by site-directed cleavage with RNAase H. SF2 is a micrococcal nuclease-resistant factor present in the nuclear extract but absent from an S100 extract. SF3 is a factor that can be preferentially inactivated by moderate heat treatment. Two additional factors (SF4A and SF4B) were identified by fractionation of the nuclear extract using spermine-agarose and CM-sepharose chromatography. SF1, SF2, and SF4B appear to be required for cleavage of the pre-mRNA at the 5' splice site and lariat formation, whereas SF3 and SF4A are only required for cleavage at the 3' splice site and exon ligation.

UI	MeSH Term	Description	Entries
D008836	Micrococcal Nuclease	An enzyme that catalyzes the endonucleolytic cleavage to 3'-phosphomononucleotide and 3'-phospholigonucleotide end-products. It can cause hydrolysis of double- or single-stranded DNA or RNA. (From Enzyme Nomenclature, 1992) EC 3.1.31.1.	Staphylococcal Nuclease,TNase,Thermonuclease,Thermostable Nuclease,Nuclease, Micrococcal,Nuclease, Staphylococcal,Nuclease, Thermostable
D009694	Nucleic Acid Precursors	Use for nucleic acid precursors in general or for which there is no specific heading.	Acid Precursors, Nucleic,Precursors, Nucleic Acid
D004722	Endoribonucleases	A family of enzymes that catalyze the endonucleolytic cleavage of RNA. It includes EC 3.1.26.-, EC 3.1.27.-, EC 3.1.30.-, and EC 3.1.31.-.	Endoribonuclease
D005914	Globins	A superfamily of proteins containing the globin fold which is composed of 6-8 alpha helices arranged in a characterstic HEME enclosing structure.	Globin
D006367	HeLa Cells	The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for, among other things, VIRUS CULTIVATION and PRECLINICAL DRUG EVALUATION assays.	Cell, HeLa,Cells, HeLa,HeLa Cell
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
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
D012261	Ribonucleoproteins	Complexes of RNA-binding proteins with ribonucleic acids (RNA).	Ribonucleoprotein
D012322	RNA Precursors	RNA transcripts of the DNA that are in some unfinished stage of post-transcriptional processing (RNA PROCESSING, POST-TRANSCRIPTIONAL) required for function. RNA precursors may undergo several steps of RNA SPLICING during which the phosphodiester bonds at exon-intron boundaries are cleaved and the introns are excised. Consequently a new bond is formed between the ends of the exons. Resulting mature RNAs can then be used; for example, mature mRNA (RNA, MESSENGER) is used as a template for protein production.	Precursor RNA,Primary RNA Transcript,RNA, Messenger, Precursors,RNA, Ribosomal, Precursors,RNA, Small Nuclear, Precursors,RNA, Transfer, Precursors,Pre-mRNA,Pre-rRNA,Pre-snRNA,Pre-tRNA,Primary Transcript, RNA,RNA Precursor,mRNA Precursor,rRNA Precursor,snRNA Precursor,tRNA Precursor,Pre mRNA,Pre rRNA,Pre snRNA,Pre tRNA,Precursor, RNA,Precursor, mRNA,Precursor, rRNA,Precursor, snRNA,Precursor, tRNA,Precursors, RNA,RNA Primary Transcript,RNA Transcript, Primary,RNA, Precursor,Transcript, Primary RNA,Transcript, RNA Primary
D012326	RNA Splicing	The ultimate exclusion of nonsense sequences or intervening sequences (introns) before the final RNA transcript is sent to the cytoplasm.	RNA, Messenger, Splicing,Splicing, RNA,RNA Splicings,Splicings, RNA