D) Overexpression of SEN1 partially suppresses the termination defects associated with deletion of the N-terminal domain. Northern blot analysis of a typical NNS-target in strains expressing the indicated SEN1 versions from pGAL in the presence of galactose. assays were performed in a ∆rrp6 background to detect the primary products of NNS-dependent termination and the U4 RNA is used as a loading control. 