Lin28B, CSDD 2, CSDD2, FLJ16517, Lin 28 homolog B C. elegans, Lin 28.2, Lin-28B, LIN28B, LN28B_HUMAN, Protein lin-28 homolog B, Protein lin-28 homolog A, Lin-28A, Zinc finger CCHC domain-containing protein 1.
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.
