Pluripotent stem cells can be created successfully through the inner cell mass (ICM), nuclear transfer, and defined-factor induction. Unfortunately, the epigenetic characteristics of the cells produced are poorly understood. In this article, we compared expression levels of enzymes involved in epigenetic modifications across six pluripotent stem cell lines. Six of the 11 genes evaluated here (Dnmt3a, Dnmt3b, Tet1, Ezh2, Mll1, and Lsd1) showed abnormally low levels of expression in the two germ-line chimeric induced pluripotent stem cell (iPSC) lines. We also conducted locus-specific analysis of DNA methylation at 9 loci. Although iPSCs did express Oct4, the Oct4 promoter region was shown to have a higher level of DNA methylation. The Xist and Line-1 repeating sequences differed relatively little in methylation level across the cell lines, but Peg3, Peg10, and H19 exhibited high degrees of variation in the pattern of DNA methylation. Meg3 in the Dlk1-Dio3 imprinting cluster was incompletely methylated in embryonic stem cells (ESCs) and nuclear transfer (nt) ESCs. However, in germ-line chimeric iPSCs, Meg3 was almost entirely methylated. ESC and ntESC lines showed twice as much Meg3 expression than in the iPSC lines. The genomic 5mC contents detected by reverse-phase high-performance liquid chromatography (HPLC) indicated that, despite their germ-line chimeric abilities, iPSCs remained incompletely reprogrammed, even though no direct evidence is shown here.

Esophageal cancer (ESCA) is the sixth leading cause of cancer-related mortality worldwide. Despite the significant impact, the molecular mechanisms underlying its initiation and progression remain poorly understood. In this study, we identified mircoRNA miR-193b-3p as a critical regulator of ESCA progression and the Remodeling and Spacing Factor 1 (RSF1) as an essential target of miR-193b-3p. Analysis of the TCGA_ESCA dataset and RT-qPCR experiments revealed that RSF1 levels are significantly elevated in ESCA and inversely correlated with miR-193b-3p levels. Using a dual-luciferase reporter assay, as well as transfection of miR-193-3p mimics or inhibitors, we confirmed RSF1 as a direct target of miR-193b-3p in ESCA cells. Transfection of miR-193b-3p suppresses ESCA cell proliferation, migration, and invasion. These effects were partially reversed by exogenous RSF1 expression. Injection of AgomiR-193b-3p into mice bearing ESCA xenografts impeded tumor growth. These findings underscore the critical role of the miR-193b-3p/RSF1 axis in esophageal cancer progression.

Compared with mammals, the bird Ig genetic system relies on gene conversion to create an Ab repertoire, with inversion of the IgA-encoding gene and very few cases of Ig subclass diversification. Although gene conversion has been studied intensively, class-switch recombination, a mechanism by which the IgH C region is exchanged, has rarely been investigated in birds. In this study, based on the published genome of pigeon (Columba livia) and high-throughput transcriptome sequencing of immune-related tissues, we identified a transcriptionally forward α gene and found that the pigeon IgH gene locus is arranged as μ-α-υ1-υ2. In this article, we show that both DNA deletion and inversion may result from IgA and IgY class switching, and similar junction patterns were observed for both types of class-switch recombination. We also identified two subclasses of υ genes in pigeon, which share low sequence identity. Phylogenetic analysis suggests that divergence of the two pigeon υ genes occurred during the early stage of bird evolution. The data obtained in this study provide new insight into class-switch recombination and Ig gene evolution in birds.