Polynucleotide 5'-kinase involved in rRNA processing. The kinase activity is required for the processing of the 32S precursor into 5.8S and 28S rRNAs, more specifically for the generation of the major 5.8S(S) form. In vitro, has both DNA and RNA 5'-kinase activities. Probably binds RNA (By similarity). Interacts with PELP1, WDR18 and SENP3. Colocalizes with pre-60S rRNP particles. Belongs to the Clp1 family. NOL9/GRC3 subfamily. Contaminating sequence. Potential poly-A sequence.