# HISTORY
07 May 2016: Updated by: TOUCHUP-v1.18
15 Mar 2016: Updated by: TOUCHUP-v1.14
25 Mar 2016: Updated by: TOUCHUP-v1.15

# molecular_function
20140909: Eukaryota_PTN000275941 has function small ribosomal subunit rRNA binding (GO:0070181) 

# cellular_component
20140909: Eukaryota_PTN000275999 is found in nucleolus (GO:0005730) 
20140909: Eukaryota_PTN000275999 is found in small-subunit processome (GO:0032040) 
20140909: Eukaryota_PTN000275941 is found in nucleolus (GO:0005730) 
20140909: Eukaryota_PTN000275941 is found in small-subunit processome (GO:0032040) 

# biological_process
20140909: cellular organisms_PTN000964819 participates in rRNA processing (GO:0006364) 
20140909: Eukaryota_PTN000275999 participates in maturation of SSU-rRNA from tricistronic rRNA transcript (SSU-rRNA, 5.8S rRNA, LSU-rRNA) (GO:0000462) 
20140909: Eukaryota_PTN000275941 participates in maturation of SSU-rRNA from tricistronic rRNA transcript (SSU-rRNA, 5.8S rRNA, LSU-rRNA) (GO:0000462) 

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

# NOTES
Background
----------
This family comprises the UTP23 and the UTP24 (aka FCF1) 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).
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).
Specific details
------------
The UTP23 and UTP24 (aka FCF1) are both amongst 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). Both are also found in the parasitic protist Entamoeba histolytica (Srivastava et al. 2014, PMID:24631428).
The PINc nuclease domain of UTP24 (aka FCF1) is required for function. In contrast, the degenerate PINc domain of UTP23 is not required for its function in biogenesis of the small ribosomal subunit (Phipps et al. 2011, PMID:21318072).

# 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).