PredcircRNA presents computational classification of circularRNA from other lncRNA using hybrid features based on multiple kernel learning.

Dear Editor,CRISPR interference (CRISPRi) is a recently developed tool used to study single guide RNA (gRNA)-mediated sequence-specific repression of transcription in both prokaryotic and eukaryotic cells [1][2][3][4][5]. Transcription initiation and elongation of a gene can be interfered by the presence of gRNA:DNA hetero-duplex/dCas9 (a catalytically inactive form of Cas9) complex in its promoter and exons. If Krüppel associated box (KRAB) domain is fused to dCas9, repression of target gene is more efficient. Likewise, fusion of a transcription activator such as VP16 (CRISPR-on) can increase target gene expression through three to four gene-specific gRNAs (up to seven) that recognize the proximal promoter of a target gene in cultured cells and in vivo [2]. We applied both CRISPRi and CRISPR-on tools in worm and zebrafish, and demonstrated here that our dCas9 fusion systems modify gene expression at or near their endogenous expression location(s) through target-specific gRNAs (ts-gRNAs).We fused dCas9 to the KRAB domain (repressor) or the VP160 domain containing 10 tandem VP16 units (activator; Figure 1A). In C. elegans, dCas9 constructs were driven by tissue-specific promoters while ts-gRNAs were under control of a U6-type RNA polymerase III promoter ( Figure 1B). Different combinations of the DNA constructs were injected into adult hermaphrodite gonads to generate transgenic worms. For zebrafish experiments, dCas9-KRAB and dCas9-VP160 mRNAs and ts-gRNAs were synthesized in vitro and injected into one-cell stage embryos ( Figure 1C), and the resulted embryos were analyzed by real-time RT-PCR and in situ hybridization. Flanking sequences, including the nuclear localization sequences (NLSs) and UTRs, were indicated in Figure 1B and 1C or described previously [6].Decrease in dpy-5 expression levels produces short body and dumpy phenotype, known as Dpy. Dbl-1 is a TGF-β family member expressed primarily in neurons and regulates lon-1 to adjust body length. When dbl-1 is overexpressed, worm body length is elongated (Lon phenotype). We targeted dpy-5 by selecting seven ts-gRNAs that recognize its non-template DNA strand of

Chinese hamster ovary (CHO) cells are widely used for biopharmaceutical protein production. One challenge limiting CHO cell productivity is apoptosis stemming from cellular stress during protein production. Here we applied CRISPR interference (CRISPRi) to downregulate the endogenous expression of apoptotic genes Bak, Bax, and Casp3 in CHO cells. In addition to reduced apoptosis, mitochondrial membrane integrity was improved and the caspase activity was reduced. Moreover, we optimized the CRISPRi system to enhance the gene repression efficiency in CHO cells by testing different repressor fusion types. An improved Cas9 repressor has been identified by applying C-terminal fusion of a bipartite repressor domain, KRAB-MeCP2, to nuclease-deficient Cas9. These results collectively demonstrate that CHO cells can be rescued from cell apoptosis by targeted gene repression using the CRISPRi system.

Mammary epithelium is comprised of an inner layer of luminal epithelial cells and an outer layer of contractile myoepithelial cells with mesenchymal properties. These two compartments interact throughout mammary morphogenesis to form branching ducts during puberty and terminate in secretory alveoli during lactation. It is not known how the myoepithelial cell lineage is specified, nor how signals in myoepithelial cells contribute to lactogenesis. Here, we show that Numb and Numbl are enriched in mammary myoepithelial cells, with their expression peaking during pregnancy. We use conditional Numb-and Numbl-knockout mouse models to demonstrate that loss of Numb/ Numbl compromised the myoepithelial layer and expanded the luminal layer, led epithelial cells to undergo epithelialto-mesenchymal transition, and resulted in lactation failure as a result of abnormal alveolar formation during pregnancy. Numb and Numbl function via repression of the Notch signaling pathway and of the p53-p21 axis during mammary gland development. These findings highlight the importance of Numb and Numbl in the control of myoepithelial cell fate determination, epithelial identity, and