Involved in ribosomal large subunit biogenesis (By similarity). Acts as both a positive transcription factor for 5S RNA genes and a specific RNA binding protein that complexes with 5S RNA in oocytes to form the 7S ribonucleoprotein storage particle. May play an essential role in the developmental change in 5S RNA gene expression. Interacts with the internal control region (ICR) of approximately 50 bases within the 5S RNA genes, is required for correct transcription of these genes by RNA polymerase III (PubMed:2253880, PubMed:1538401, PubMed:1762917). Also binds the transcribed 5S RNA's (By similarity). Synthesized in oocytes and, in much lower levels, in somatic cells. The levels follow the transcriptional activity of oocyte type 5S RNA genes during embryogenesis, present in very high levels in maturing oocytes when oocyte type 5S genes are being expressed, and in much lower levels in somatic cells where the oocyte type genes are not expressed. The N-terminus is blocked.