This gene encodes a nucleotidyl transferase that functions as both a terminal uridylyltransferase and a nuclear poly(A) polymerase. The encoded enzyme specifically adds and removes nucleotides from the 3′ end of small nuclear RNAs and select mRNAs and may function in controlling gene expression and cell proliferation.[provided by RefSeq, Apr 2009],catalytic activity:UTP + RNA(n) = diphosphate + RNA(n+1).,function:Highly specific terminal uridylyltransferase that exclusively accepts U6 snRNA as substrate. U6 snRNA is unique in that nucleotides are both added to and removed from its 3′-end. U6-TUTase is responsible for a controlled elongation reaction that results in the restoration of the four 3′-terminal UMP-residues found in newly transcribed U6 snRNA.,PTM:Phosphorylated upon DNA damage, probably by ATM or ATR.,similarity:Contains 1 RRM (RNA recognition motif) domain.,