Purified 6xHis-tagged WT Npl3 or mutant Npl3-LSNK were incubated with double stranded telomeric DNA (dsTelo), single stranded telomeric DNA (ssTelo), G-rich RNA (TeloRNA), all derived from chromosome I-L, or non-telomeric double stranded DNA (dsDNA). Oligonucleotide sequences are listed in Table SII. For the right most panel, WT Npl3 (25nM) was mixed with unlabeled ssTelo, TeloRNA, or dsDNA (1-, 2-, 5-, or 10- fold excess) prior to the addition of radiolabeled dsTelo oligo. Percent Npl3-dsTelo complex is the average density of each protein complex (minus background) relative to the Npl3-dsTelo binding with no unlabelled competitor. Non-specific bands are indicated by asterisks or open triangles (secondary structures formed by G-rich dsTelo oligos). Figure is representative of two to three independent experiments.