機能Acts as a suppressor of microRNA (miRNA) biogenesis by specifically binding the precursor let-7 (pre-let-7), a miRNA precursor. Acts by binding pre-let-7 and recruiting ZCCHC11/TUT4 uridylyltransferase, leading to the terminal uridylation of pre-let-7. Uridylated pre-let-7 miRNAs fail to be processed by Dicer and undergo degradation. Specifically recognizes the 5'-GGAG-3' motif in the terminal loop of pre-let-7. Also recognizes and binds non pre-let-7 pre-miRNAs that contain the 5'-GGAG-3' motif in the terminal loop, leading to their terminal uridylation and subsequent degradation. Mediates MYC-mediated let-7 repression. Isoform 1, when overexpressed, stimulates growth of the breast adenocarcinoma cell line MCF-7. Isoform 2 has no effect on cell growth.
組織特異性High expression in testis, fetal liver, placenta and in hepatocellular carcinoma (HCC). Isoform 1 is only detected in moderately and poorly differentiated HCC tissues and placenta (at protein level). Isoform 2 is detected in fetal liver, non-tumor liver tissues, as well as well-differentiated tumor tissues (at protein level).
配列類似性Belongs to the lin-28 family. Contains 2 CCHC-type zinc fingers. Contains 1 CSD (cold-shock) domain.
細胞内局在Cytoplasm. Nucleus. Predominantly cytoplasmic at G1 phase, accumulates in the nucleus in S and G2 phases. The frequency of nuclear localization in S and in G2 phases is 60% and 30%, respectively.