7-EAA is taken up by HeLa cells and incorporated into cellular RNA. A) Detection of biotin-labeled RNA after click reaction with biotin-azide (M) biotinylated molecular weight markers in kb, (1) Sample isolated from cells grown in absence of 7-EAA, treated with RNase V1; (2) Sample isolated from cells grown in the presence of 100 μM 7EAA, treated with RNase V1; (3) Sample isolated from cells grown in the absence of 7-EAA, no RNase V1 treatment; (4) Sample isolated from cells grown in presence of 100 μM 7-EAA, no RNase V1 treatment. B) Same as in A) with ethidium bromide (EtBr) detection instead of biotin detection.