Accumulation of pre-let-7g and downregulation of mature let-7g with the depletion of EWS.
EWS functions in RNA splicing and transcription by encoding an RNA binding protein, which results in the chromosomal translocation t(11;22)(q24;q12) found in Ewing sarcoma. EWS interacts with the microprocessor complex involving Drosha and DGCR8, which play roles as the cofactors of primary microRNA processing. However, the role of EWS in microRNA biogenesis has not been investigated. Here, we show that endogenous EWS interacts with endogenous Drosha by IP-western blotting. In addition, EWS knockout mouse decreased the expression of Drosha. The depletion of EWS results in the accumulation of precursor let-7g but down-regulates mature let-7g in U2OS cells. Consistently, mature let 7g was suppressed in both Ewing sarcoma cell and primary Ewing sarcoma. Also, expression levels of Dicer and CCND1 (Cyclin D1), which are known target genes of the let-7 family were upregulated. Our findings suggest that EWS mediates generation of mature let-7g from pre-let-7g.
Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20871, USA. eunjungs93@gmail.com
Eun Jung
EJ
Sohn
Junhong
J
Park
Soo-im
SI
Kang
Yun-Ping
YP
Wu
D000818:Animals; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D015536:Down-Regulation; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D035683:MicroRNAs / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing; D034802:RNA-Binding Protein EWS / Q000235:genetics / Q000378:metabolism*; D043244:Ribonuclease III / Q000378:metabolism; D012512:Sarcoma, Ewing / Q000235:genetics / Q000378:metabolism*
D035683:MicroRNAs; D012322:RNA Precursors; D034802:RNA-Binding Protein EWS; C487931:mirnlet7 microRNA, human; C542687:mirnlet7 microRNA, mouse; C513400:Drosha protein, mouse; D043244:Ribonuclease III