go_id,ontology,go_term,term_definition,evidence GO:0000398,BP,"mRNA splicing, via spliceosome","The joining together of exons from one or more primary transcripts of messenger RNA (mRNA) and the excision of intron sequences, via a spliceosomal mechanism, so that mRNA consisting only of the joined exons is produced.",IGI GO:0005654,CC,nucleoplasm,"That part of the nuclear content other than the chromosomes or the nucleolus.",IDA GO:0015030,CC,"Cajal body","A class of nuclear body, first seen after silver staining by Ramon y Cajal in 1903, enriched in small nuclear ribonucleoproteins, and certain general RNA polymerase II transcription factors; ultrastructurally, they appear as a tangle of coiled, electron-dense threads roughly 0.5 micrometers in diameter; involved in aspects of snRNP biogenesis; the protein coilin serves as a marker for Cajal bodies. Some argue that Cajal bodies are the sites for preassembly of transcriptosomes, unitary particles involved in transcription and processing of RNA.",IEA GO:0016607,CC,"nuclear speck","A discrete extra-nucleolar subnuclear domain, 20-50 in number, in which splicing factors are seen to be localized by immunofluorescence microscopy.",IEA GO:0044822,MF,"poly(A) RNA binding","Interacting non-covalently with a poly(A) RNA, a RNA molecule which has a tail of adenine bases.",IDA GO:0047485,MF,"protein N-terminus binding","Interacting selectively and non-covalently with a protein N-terminus, the end of any peptide chain at which the 2-amino (or 2-imino) function of a constituent amino acid is not attached in peptide linkage to another amino-acid residue.",IDA GO:0070742,MF,"C2H2 zinc finger domain binding","Interacting selectively and non-covalently with a C2H2-type zinc finger domain of a protein. The C2H2 zinc finger is the classical zinc finger domain, in which two conserved cysteines and histidines co-ordinate a zinc ion.",IPI GO:0071013,CC,"catalytic step 2 spliceosome","A spliceosomal complex that contains three snRNPs, including U5, bound to a splicing intermediate in which the first catalytic cleavage of the 5' splice site has occurred. The precise subunit composition differs significantly from that of the catalytic step 1, or activated, spliceosome, and includes many proteins in addition to those found in the associated snRNPs.",IDA