Figure 2: tRFs are present in the ribosome-associated RNome. Northern blot analyses of tRFs confirm the presence of class I (a), class II (b), and class III (c) tRFs in the ribosome-associated RNA fraction. The full-length tRNA signals are depicted by black arrows and tRFs by open arrow heads. Approximate lengths of the fragments, as deduced from RNA markers, are indicated. tRFs corresponding to the sequence reads of the cDNA library (Table 1) are underlined. RNA was isolated from unstressed H. volcanii cells (no stress), or cells grown under different permanent environmental stress conditions (ultraviolet stress (UV), high pH (pH↑), 0.9 M NaCl (NaCl), 300 mM MgSO4 (Mg↑)). The 5S rRNA (asterisk) of ethidium bromide stained gels served as loading controls.