# HISTORY
26 Mar 2016: Updated by: TOUCHUP-v1.15
16 Mar 2016: Updated by: TOUCHUP-v1.14

# molecular_function

# cellular_component
20150814: Eukaryota_PTN000469546 is found in U2 snRNP (GO:0005686) 
20150814: Eukaryota_PTN000469546 is found in U12-type spliceosomal complex (GO:0005689) 
20150814: Eukaryota_PTN000469546 is found in precatalytic spliceosome (GO:0071011) 
20150814: Excavarus_PTN001076713 is NOT found in U12-type spliceosomal complex (GO:0005689) 
20150814: Chromadorea_PTN001076683 is NOT found in U12-type spliceosomal complex (GO:0005689) 
20150814: Ascomycota_PTN000469586 is NOT found in U12-type spliceosomal complex (GO:0005689) 
20150814: Alveolata_PTN001841910 is NOT found in U12-type spliceosomal complex (GO:0005689) 
20150814: Dictyostelium_PTN001076708 is NOT found in U12-type spliceosomal complex (GO:0005689) 

# biological_process
20150814: Eukaryota_PTN000469546 participates in mRNA splicing, via spliceosome (GO:0000398) 

# WARNINGS - THE FOLLOWING HAVE BEEN REMOVED FOR THE REASONS NOTED

# NOTES
This family contains two subunits of the Sf3b subcomplex, which is part of the U12 snRNP (Will et al. 2004, PMID:15146077; Turunen et al. 2013, PMID:23074130) as well as being part of the U2 snRNP (Turunen et al. 2013, PMID:23074130).
It is believed that the last eukaryotic common ancestor (LECA) possessed both the major (U2-type) and minor (U12-type) spliceosomes and that the current diversity of organisms across multiple taxonomic groups which lack the minor U12-type has been generated by multiple loss events of the minor U12-type spliceosome (Lopez et al. 2008, PMID:18390578; Bartschat & Samuelsson 2010, PMID:20149226; Turunen et al. 2013, PMID:23074130; Irimia and Roy 2014, PMID:24890509).
Comment on annotation propagations:
-------------------------------
Based on the current views on the phylogeny of the major U2-type and minor U12-type spliceosomes, I have propagated both the U2-type and the U12-type terms to the root node Eukaryota_PTN000250426 (ignoring the duplication node PTN000949721 that is the actual root of the tree).
Then, I have blocked propagation of the U12-type terms in multiple places based on the phylogenetic analysis in Bartschat & Samuelsson 2010 (PMID:20149226) and Turunen et al. 2013 (PMID:23074130) and the computational work of Lopez et al. 2008 (PMID:18390578) to determine the phylogenetic distribution of the major and minor spliceosomes.
- In some places, I have felt confident that I could place the block at the node representing an entire taxonomic group, e.g. Ascomycetes, Chromodorea (a group within Nemotoda), Alveolata (includes Plasmodium & Tetrahymena), Excavarus (includes Trichomonas, Trypanosoma, and Leishmania).
- In other places, such as the Basidiomycetes where there are members of this taxonomic group thought to still contain the minor U12-type, I have placed the block on the individual species currently represented in the tree if they are thought to have lost it.
- I have also blocked the U12-type terms in several individual species that appear to be the sole representative of their group included in the Panther Tree, e.g. Chlamydomonas reinhardtii (green algae), Entamoeba histolytica, and Thalassiosira pseudonana.

# REFERENCE
Annotation inferences using phylogenetic trees
The goal of the GO Reference Genome Project, described in PMID 19578431, is to provide accurate, complete and consistent GO annotations for all genes in twelve model organism genomes. To this end, GO curators are annotating evolutionary trees from the PANTHER database with GO terms describing molecular function, biological process and cellular component. GO terms based on experimental data from the scientific literature are used to annotate ancestral genes in the phylogenetic tree by sequence similarity (ISS), and unannotated descendants of these ancestral genes are inferred to have inherited these same GO annotations by descent. The annotations are done using a tool called PAINT (Phylogenetic Annotation and INference Tool).