Luna Joseph M, Barajas Juan M, Teng Kun-Yu, Sun Hui-Lung, Moore Michael J, Rice Charles M, Darnell Robert B, Ghoshal Kalpana
Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA; Laboratory of Molecular Neuro-Oncology and Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA.
Department of Pathology, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
Mol Cell. 2017 Aug 3;67(3):400-410.e7. doi: 10.1016/j.molcel.2017.06.025. Epub 2017 Jul 20.
MicroRNA-122, an abundant and conserved liver-specific miRNA, regulates hepatic metabolism and functions as a tumor suppressor, yet systematic and direct biochemical elucidation of the miR-122 target network remains incomplete. To this end, we performed Argonaute crosslinking immunoprecipitation (Argonaute [Ago]-CLIP) sequencing in miR-122 knockout and control mouse livers, as well as in matched human hepatocellular carcinoma (HCC) and benign liver tissue to identify miRNA target sites transcriptome-wide in two species. We observed a majority of miR-122 binding on 3' UTRs and coding exons followed by extensive binding to other genic and non-genic sites. Motif analysis of miR-122-dependent binding revealed a G-bulged motif in addition to canonical motifs. A large number of miR-122 targets were found to be species specific. Upregulation of several common mouse and human targets, most notably BCL9, predicted survival in HCC patients. These results broadly define the molecular consequences of miR-122 downregulation in hepatocellular carcinoma.
微小RNA-122是一种丰富且保守的肝脏特异性微小RNA，它调节肝脏代谢并发挥肿瘤抑制作用，然而，对miR-122靶标网络进行系统而直接的生化阐释仍不完整。为此，我们在miR-122基因敲除小鼠和对照小鼠肝脏中，以及在匹配的人类肝细胞癌（HCC）和良性肝组织中进行了AGO蛋白交联免疫沉淀（AGO-CLIP）测序，以在两个物种中全转录组范围鉴定微小RNA靶位点。我们观察到大多数miR-122结合在3'非翻译区（UTR）和编码外显子上，随后广泛结合到其他基因和非基因位点。对miR-122依赖性结合的基序分析揭示，除了典型基序外，还有一个G凸起基序。发现大量miR-122靶标具有物种特异性。几种常见的小鼠和人类靶标的上调，最显著的是BCL9，可预测HCC患者的生存率。这些结果广泛地定义了肝细胞癌中miR-122下调的分子后果。
