This gene encodes a 5′-3′ exonuclease that promotes transcription termination at cotranscriptional cleavage sites. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Dec 2015],catalytic activity:Exonucleolytic cleavage in the 5′- to 3′-direction to yield nucleoside 5′-phosphates.,function:Possesses 5′->3′ exoribonuclease activity (By similarity). May promote the termination of transcription by RNA polymerase II. During transcription termination, cleavage at the polyadenylation site liberates a 5′ fragment which is subsequently processed to form the mature mRNA and a 3′ fragment which remains attached to the elongating polymerase. The processive degradation of this 3′ fragment by this protein may promote termination of transcription.,similarity:Belongs to the 5′-3′ exonuclease family. XRN2/RAT1 subfamily.,similarity:Contains 1 CCHC-type zinc finger.,tissue specificity:Expressed in the spleen, thymus, prostate, testis, ovary, small intestine, colon, peripheral blood leukocytes, heart, brain, placenta, lung, liver, skeletal muscle, kidney, and pancreas. Isoform 2 is expressed predominantly in peripheral blood leukocytes.,