Protein required for nuclear retention of unspliced pre-mRNAs; required along with Mlp1p and Pml1p; anchored to the nuclear pore complex through an interaction between its bimodular nuclear basket-interaction domain (NuBaID) and Mlp1p and Mlp2p; localizes to the nuclear basket enables linkage between subpopulations of Mlp1p; associates with the subset of nuclear pores farthest from the nucleolus; homologous to human ZC3HC1, a NuBaID containing protein