FIGURE 3.

Affinity purification of a 94-nt RNA on small and large scales analyzed on ethidium bromide stained 12% denaturing polyacrylamide gels. (A) Purification of a 100-μL transcription using a QIAGEN Ni-NTA spin column. (Lane Tx) The raw transcription; (lane FT) the column flowthrough; (lanes W1–W3) the three wash steps; (lanes E1,E2) the two 200-μL elutions; (lane S) the imidazole elution. Bands “a”, “b,” and “c” denote the full-length transcript, 3′-tag, and 94-nt product, respectively. (B) Purification of a 3.25-mL transcription using a 3.0-mL Ni-NTA agarose gravity column. Lanes and bands are marked the same as in A, except that there is a third elution step (lane E3).