tRNA-derived microRNA modulates proliferation and the DNA damage response and is down-regulated in B cell lymphoma

Sequencing studies from several model systems have suggested that diverse and abundant small RNAs may be derived from tRNA, but the function of these molecules remains undefined. Here, we demonstrate that one such tRNA-derived fragment, cloned from human mature B cells and designated CU1276, in fact possesses the functional characteristics of a microRNA, including a DICER1-dependent biogenesis, physical association with Argonaute proteins, and the ability to repress mRNA transcripts in a sequence-specific manner. Expression of CU1276 is abundant in normal germinal center B cells but absent in germinal center-derived lymphomas, suggesting a role in the pathogenesis of this disease. Furthermore, CU1276 represses…