Project description:To identify ZNF506 genome-wide target sites, we performed ChIP-seq assay and found that ZNF506 binding sites enriched at PBS-Pro-containing ERV subfamilies (ERVPs) and further motif calling analysis showed that ZNF506 binds to PBS-Pro sequences, promoting formation of H3K9me3 modifications at binding regions. And ChIP-seq assay also indicated that the distinction of H3K9me3 signals closed to ZNF506 peak regions between ZNF506 overexpressing (OE) HEK293T cells and ZNF506 Knockout (KO) HEK293T cells was correlated with the different recruitment of corepressor KAP1. The ChIP-seq experiments using GFP antibodies and H3K9me3 antibodies on ZNF506-GFP OE HEK293T cell lines, and ZNF417-GFP OE HEK293T cell lines were used as controls for H3K9me3 ChIP. Also, the ChIP-seq experiments were performed using H3K9me3 antibodies and KAP1 antibodies on ZNF506 KO HEK293T cells and ZNF506 OE HEK293T cells.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes