Modulation of specific cell cycle phases in human embryonic stem cells by lncRNA RNA decoys

Recent studies have shown that long noncoding RNAs (lncRNAs) are crucial regulators of human embryonic stem cells (hESCs). However, modes of actions of lncRNAs in hESCs are not well illustrated. Here, we predicted a regulatory network in hESCs in which lncRNAs interact with TFs and thereby control the expressions of downstream targets of TFs. The predicted network is comprised of 2289 3‐motif subgraphs which are characterized by 3 nodes: (i) a lncRNA which is predicted to interact with (ii) a TF and (iii) a gene which is a target of TF and coexpressing with lncRNA. We performed functional annotation of the network by identifying hub nodes followed by pathway enrichment study, which unveiled an active G1‐S cell cycle phase transition‐specific subnetwork that encompasses 2 lncRNAs, MALAT1 and DANCR. Our analysis revealed that MALAT1 and DANCR might be playing key roles in G1‐S phase transition by acting as RNA decoy via interacting with crucial stemness maintaining TFs. We predicted that MALAT1 possibly compete with DNMT1 and CDCA7 genes to bind to E2F1 thereby interrupting repression of DNMT1 and activation of CDCA7 by E2F1 in hESCs, whereas DANCR possibly competes with IPO7 gene to bind to MYC thereby interrupting MYC‐mediated activation of IPO7 in hESCs. Both of these are conjectured to contribute to rapid G1‐S phase transition aiding in stemness maintenance of hESCs. This study presents a crucial TF target cross talks mediated by lncRNAs in hESCs regulating its properties which needs further investigation.     

From blastocyst to gastrula: gene regulatory networks of embryonic stem cells and early mouse embryogenesis

To date, many regulatory genes and signalling events coordinating mammalian development from blastocyst to gastrulation stages have been identified by mutational analyses and reverse-genetic approaches, typically on a gene-by-gene basis. More recent studies have applied bioinformatic approaches to generate regulatory network models of gene interactions on a genome-wide scale. Such models have provided insights into the gene networks regulating pluripotency in embryonic and epiblast stem cells, as well as cell-lineage determination in vivo. Here, we review how regulatory networks constructed for different stem cell types relate to corresponding networks in vivo and provide insights into understanding the molecular regulation of the blastocyst–gastrula transition.