This is a family of proteins conserved from yeasts to human. Subunit A34.5 of RNA polymerase I is a non-essential subunit which is thought to help Pol I overcome topological constraints imposed on ribosomal DNA during the process of transcription [1].

1: A34.5, a nonessential component of yeast RNA polymerase I, cooperates with subunit A14 and DNA topoisomerase I to produce a functional rRNA synthesis machine. Gadal O, Mariotte-Labarre S, Chedin S, Quemeneur E, Carles C, Sentenac A, Thuriaux P; Mol Cell Biol 1997;17:1787-1795. PMID:9121426