Lin28B Antibody (YA709),MedChemexpress,HY-P80211

Lin28B is a suppressor of microRNA (miRNA) biogenesis, including let-7 and potentially miR107, miR-143, and miR-200c. It binds primary let-7 transcripts (pri-let-7), such as pri-let-7g and pri-let-7a-1, and sequesters them in the nucleolus, away from the microprocessor complex, thereby preventing their processing into mature miRNA. Lin28B does not act on pri-miR21. The repression of let-7 expression is essential for normal development and helps maintain the pluripotent state of embryonic stem cells by blocking let-7-mediated differentiation. When overexpressed, Lin28B recruits the ZCCHC11/TUT4 uridylyltransferase to pre-let-7 transcripts, leading to their terminal uridylation and degradation, though this activity may not be physiologically relevant, as LIN28B-mediated inhibition of let-7 miRNA maturation appears to be ZCCHC11-independent. Interaction with target pre-miRNAs occurs via a 5'-GGAG-3' motif in the pre-miRNA terminal loop. By similarity, Lin28B mediates MYC-induced let-7 repression. Overexpression of isoform 1 stimulates growth of the breast adenocarcinoma cell line MCF-7, while isoform 2 has no effect on cell growth.