Frequent deletions and down-regulation of micro- RNA genes miR15 and miR16 at 13q14 in chronic lymphocytic leukemia
George Adrian Calin, Calin Dan Dumitru, Masayoshi Shimizu, Roberta Bichi, Simona Zupo, Evan Noch, Hansjuerg Aldler, Sashi Rattan, Michael Keating, Kanti Rai, Laura Rassenti, Thomas Kipps, Massimo Negrini, Florencia Bullrich, Carlo M. Croce- Multidisciplinary
Micro-RNAs ( miR genes) are a large family of highly conserved noncoding genes thought to be involved in temporal and tissue-specific gene regulation. MiRs are transcribed as short hairpin precursors (≈70 nt) and are processed into active 21- to 22-nt RNAs by Dicer, a ribonuclease that recognizes target mRNAs via base-pairing interactions. Here we show that miR15 and miR16 are located at chromosome 13q14, a region deleted in more than half of B cell chronic lymphocytic leukemias (B-CLL). Detailed deletion and expression analysis shows that miR15 and miR16 are located within a 30-kb region of loss in CLL, and that both genes are deleted or down-regulated in the majority (≈68%) of CLL cases.