Acts as a negative regulator of nuclear pre-mRNA 3'-end processing (mRNA polyadenylation) (Probable) (PubMed:26588990). Plays a role in tissue-specific expression of protein isoforms by regulating differential processing of pre-mRNA 3'-end (alternative polyadenylation) (PubMed:26588990, PubMed:28087624). In neurons, regulates alternative polyadenylation of specific mRNAs including unc-44 and dlk-1 by interacting with phosphatase ssup-72 and thus preventing ssup-72 dephosphorylation of RNA polymerase II subunit ama-1 (PubMed:26588990). Specifically, alters the usage of internal polyadenylation sites (PAS) to promote the production of neuron-specific unc-44 isoform and dlk-1 isoform c, both required for normal synapse and axon development (PubMed:26588990). Conversely, in the epidermis, by inhibiting ssup-72 function, promotes the usage of an internal PAS preventing the production of one of unc-44 isoforms (PubMed:28087624). In neurons, also negatively regulates protein levels of pre-RNA processing protein psf-2 (PubMed:20530551). May interact (via C-terminus) with ssup-72; the interaction may prevent ssup-72 binding to RNA polymerase II subunit ama-1. Also localizes to a small subnuclear ring in neurons. In neurons, partially co-localizes with pfs-2 in the nucleus. Expressed in germline, oocytes, epidermis, pharyngeal bulb and neurons.