rna polymerase ii pol ii transcription termination by the nrd1p nab3p sen1p nns pathway is critical for the production of stable noncoding rnas and the control of pervasive transcription in saccharomyces cerevisiae to uncover determinants of nns termination we mapped the 3 ends of nns terminated transcripts genome wide we found that nucleosomes and specific dna binding proteins including the general regulatory factors grfs reb1p rap1p and abf1p and pol iii transcription factors enhance the efficiency of nns termination by physically blocking pol ii progression the same dna bound factors that promote nns termination were shown previously to define the 3 ends of okazaki fragments synthesized by pol δ during dna replication reduced binding of these factors results in defective nns termination and pol ii readthrough furthermore inactivating nns enables pol ii elongation through these roadblocks demonstrating that effective pol ii termination depends on a synergy between the nns machinery and obstacles in chromatin consistent with this finding loci exhibiting pol ii readthrough at grf binding sites are depleted for upstream nns signals overall these results underscore how rna termination signals influence the behavior of pol ii at chromatin obstacles and establish that common genomic elements define boundaries for both dna and rna synthesis machineries.