Pre-mRNA splicing occurs in two sequential transesterification steps. The protein encoded by this gene is a splicing factor that has been found to be essential during the second catalytic step in the pre-mRNA splicing process. It associates with the spliceosome and contains a zinc knuckle motif that is found in other splicing factors and is involved in protein-nucleic acid and protein-protein interactions. [provided by RefSeq, Jul 2008],domain:The CCHC-type zinc finger is required to retain the protein within the nucleus and prevent its shuttle back to the cytoplasm via the CRM1 pathway.,function:Participates in the second catalytic step of pre-mRNA splicing, when the free hydroxyl group of exon I attacks the 3′-splice site to generate spliced mRNA and the excised lariat intron. Required for holding exon 1 properly in the spliceosome and for correct AG identification when more than one possible AG exists in 3′-splicing site region. May be involved in the activation of proximal AG. Probably also involved in alternative splicing regulation.,similarity:Belongs to the SLU7 family.,similarity:Contains 1 CCHC-type zinc finger.,subcellular location:Predominantly nuclear. Shuttling between the nucleus and the cytoplasm is regulated by the CCHC-type zinc finger. Upon UV-C stress stimulus, the nuclear concentration of the protein decreases, affecting alternative splicing.,subunit:Component of late spliceosomal complexes. Associates with the spliceosome prior to recognition of the 3′-splice site for step II, probably during catalysis of step I.,