# molecular_function 20140929: Eukaryota_PTN000356711 has function ubiquitin-protein transferase activity (GO:0004842) # cellular_component 20140929: Eukaryota_PTN000356653 located in small-subunit processome (GO:0032040) 20140929: Eukaryota_PTN000356653 located in Pwp2p-containing subcomplex of 90S preribosome (GO:0034388) 20140929: Eukaryota_PTN000356653 located in nucleolus (GO:0005730) 20140929: Eukaryota_PTN000356711 located in catalytic step 2 spliceosome (GO:0071013) 20140929: Eukaryota_PTN000356711 located in Prp19 complex (GO:0000974) 20140929: Eukaryota_PTN000356711 located in U2-type catalytic step 1 spliceosome (GO:0071006) # biological_process 20140929: Eukaryota_PTN000356653 participates in rRNA processing (GO:0006364) 20140929: Eukaryota_PTN000356711 participates in generation of catalytic spliceosome for first transesterification step (GO:0000349) # Notes This family contains two subclades of WD repeat proteins, PRP19 (aka PRPF19) and UTP21 (aka WDR36). PRP19 subclade: ------------- The PRP19 subclade is the namesake member of the PRP19 complex that is part of spliceosome. In addition to containing multiple WD repeat domains, it contains an N-terminal U box domain that possesses ubiquitin-protein transferase activity (PMID:12627222, PMID:11425423, PMID:19825583). As part of the PRP19 complex, it is involved in spliceosomal assembly, specifically in the structural rearrangements that free U4 from the spliceosome to generate the catalytic complex that mediates the first splicing transesterification reaction (PMID:8248176). UTP21 subclade: ------------- This subclade comprises the UTP21 (aka WDR36) subunits of the ribosomal Small Subunit Processome, also called the SSU Processome, a large complex which is involved in the initial cleavages of the primary rRNA transcript to separate the small ribosomal subunit (SSU) rRNA from the remainder of the transcript and the biogenesis of the small ribosomal subunit. The SSU processome was originally identified and characterized from S. cerevisiae (Dragon et al. 2002, PMID:12068309; Gallagher et al. 2004, PMID:15489292; Bernstein et al. 2004, PMID:15590835; and reviewed in Phipps et al. 2011, PMID:21318072). As of September 2014, it has begun to be characterized experimentally from other species such as human (Turner et al. 2012, PMID:22418842; Sato et al. 2013, PMID:24219289; and Hu et al. 2011, PMID:21078665), zebrafish (Wilkins et al. 2013, PMID:24147052), and mouse (Gallenberger et al. 2011, PMID:21051332). The UTP21 subunit is a confirmed subunit of the SSU processome, and specifically part of the UtpB, aka Pwp2-containing, subcomplex (Phipps et al. 2011, PMID:21318072). Feng et al. 2013 (PMID:24214024) performed an extensive computational analysis from 77 completely sequenced eukaryotic genomes, including representatives of the five eukaryotic supergroups: Opisthokonts, Amoebozoa, Plantae, Excavates, and Chromalveolates, and compared these to sequences from both prokaryotic and Archaeal species for all 51 confirmed and 26 likely SSU processome subunits in S. cerevisiae as indicated in Phipps et al. 2011 (PMID:21318072). In addition, Srivastava et al. have identified SSU processome subunits in the parasitic protist Entamoeba histolytica (PMID:24631428). UTP21 is one of the 51 confirmed proteins of the S. cerevisiae SSU processome (Phipps et al. 2011, PMID:21318072)) and is highly conserved across the 77 eukaryotic species, as listed in Table 1 of Feng et al. 2013 (PMID:24214024). It is also found in the parasitic protist Entamoeba histolytica (Srivastava et al. 2014, PMID:24631428). Annotation comments: --------------------- No MF annotations were propagated in this subclade. There were experimental MF annotations for human WDR36 to "poly(A) RNA binding" (GO:0044822) from a high throughput study: PMID:22658674. Between the fact that this was a high throughput experiment, the fact that this protein is normally part of a large complex, and the fact that it is not clear that poly(A) RNA binding is biologically relevant, I have chosen not to propagate this MF annotation. 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).