This domain is found at the N terminal of the helicase SEN1. SEN1 is a Pol II termination factor for noncoding RNA genes [2]. The N terminal of SEN1, unlike the C terminal, is not required for growth [1].

1: SEN1, a positive effector of tRNA-splicing endonuclease in Saccharomyces cerevisiae. DeMarini DJ, Winey M, Ursic D, Webb F, Culbertson MR; Mol Cell Biol. 1992;12:2154-2164. PMID:1569945

2: Genome-wide distribution of yeast RNA polymerase II and its control by Sen1 helicase. Steinmetz EJ, Warren CL, Kuehner JN, Panbehi B, Ansari AZ, Brow DA; Mol Cell. 2006;24:735-746. PMID:17157256