Pre-mRNA Processing Factor 19 (PRPF19)

PSO4 is the human homolog of yeast Pso4, a gene essential for cell survival and DNA repair . PSO4 shares 38% amino acid identity with S. cerevisiae Pso4. SDS-PAGE indicated that PSO4 has an apparent molecular mass of 55 kD.PSO4 readily bound plasmid DNA substrates, including closed circular plasmid DNA, indicating that PSO4 binds in a sequence-independent manner and does not require free DNA ends for binding. PSO4 expression was induced 15- to 30-fold in a normal human fibroblast cell line by gamma irradiation and chemical mutagens, but not by ultraviolet irradiation. Loss of PSO4 expression induced by small interfering RNA resulted in accumulation of double-strand breaks, apoptosis, and decreased cell survival after DNA damage.