Does not have cyclase activity. Plays a role in 40S- ribosomal-subunit biogenesis in the early pre-rRNA processing steps at sites A0, A1 and A2 that are required for proper maturation of the 18S RNA (By similarity).
Billy, Wegierski, Nasr, Filipowicz: "Rcl1p, the yeast protein similar to the RNA 3'-phosphate cyclase, associates with U3 snoRNP and is required for 18S rRNA biogenesis." in: The EMBO journal, Vol. 19, Issue 9, pp. 2115-26, (2000) (PubMed).