Project description:Since VitaminA and VitaminC are pleiotropic vitamins, and both can promote reprogramming, we want to know the relationship between them. We use serum-free N2B27(B27 minus Va) medium to generate iPS with OKSM virus infecting OG2 MEF, and collect mRNA at day7 under 10nM and 1uM Va with or without Vc. We found tha both Va and Vc promote reprogramming, and the genes upregulated by Va and Va had overlpped more than 80%.
Project description:Tet1 is a hydroxylase known for its role in the conversion of 5-methylcytosines (5mC) to 5-hydroxymethylcytosines (5hmC) involved in the possible active demethylation process and gene expression regulation. As somatic cell reprogramming involves the re-activation of pluripotency genes and the silencing of somatic ones, it remains unclear the role of Tet1 in the reprogramming process. Here, we performed RNAseq for WT and knocking down Tet1 in two pre-iPSCs cell lines, pre2-2 and pre3. Using two pre-iPSCs cell lines: pre2-2 and pre3, cultured by mES medium(+lif), transfected siCtrl/siTet1 siRNA or non-treatment, then, after 16h, the medium were replaced by mES(+lif) medium plus Vc(50ug/ml), total RNA was extracted after another 32h later for RNAseq.
Project description:Somatic cells acclimate to changes in the environment by temporary reprogramming. Much has been learned about transcription factors that induce these cell-state switches in both plants and animals, but how cells rapidly modulate their proteome remains elusive. Here, we show rapid induction of autophagy during temporary reprogramming in plants triggered by phytohormones, immune and danger signals. Quantitative proteomics following sequential reprogramming revealed that autophagy is required for timely decay of previous cellular states and for tweaking the proteome to acclimate to the new conditions. Signatures of previous cellular programs thus persist in autophagy deficient cells, affecting cellular decision-making. Concordantly, autophagy deficient cells fail to acclimatize to dynamic climate changes. Similarly, they have defects in dedifferentiating into pluripotent stem cells, and redifferentiation during organogenesis. These observations indicate that autophagy mediates cell state switches that underlie somatic cell reprogramming in plants and possibly other organisms, and thereby promotes phenotypic plasticity.
Project description:Tet1 is a hydroxylase known for its role in the conversion of 5-methylcytosines (5mC) to 5-hydroxymethylcytosines (5hmC) involved in the possible active demethylation process and gene expression regulation1-5.M-BM- As somatic cell reprogramming involves the re-activation of pluripotency genes and the silencing of somatic ones6, it remains unclear whether Tet1 plays a positive or negative role in the reprogramming process. Here we show that Tet1 deficiency enhances reprogramming and its overexpression impairs reprogramming. Mechanistically, we demonstrated that Tet1 represses the early obligatory process of mesenchymal to epithelial transition (MET) during reprogramming7,8. Thus, our findings not only define a negative role for Tet1 in somatic cell reprogramming, but also suggest that the Tet enzymes regulate cell fate through distinctive mechanisms. Examination of genome DNA hmC modifications in 2 conditions: individually overexpressed Tet1CD or Tet2CD during MEF reprogramming; Examination of mRNA levels in five different conditions: individually overexpressed DR or Tet1CD or Tet1CDmut or Tet2CD or Tet2CDmut, during MEF reprogrammig.
Project description:Tet1 is a hydroxylase known for its role in the conversion of 5-methylcytosines (5mC) to 5-hydroxymethylcytosines (5hmC) involved in the possible active demethylation process and gene expression regulation. As somatic cell reprogramming involves the re-activation of pluripotency genes and the silencing of somatic ones, it remains unclear the role of Tet1 in the reprogramming process. Here, we performed hMeDIP-seq and RNA-seq during somatic cells reprogramming with Tet1 over expression to invest the effect of Tet1.
Project description:Polycomb repressive complex 1 (PRC1) plays essential roles in cell fate determination. Recent studies have found that the composition of mammalian PRC1 is particularly varied and complicated, whereas the function of such variant PRC1 complexes on cell fate determination remains unknown. Here we show that Kdm2b, which recruits a variant PRC1 complex (PRC1.1) to CpG islands (CGIs), elevates Oct4 induced somatic reprogramming. Interaction with PRC1 is critical for Kdm2b’s promotion on the process of induced pluripotency. Furthermore, we find that bone morphogenetic proteins (BMPs) repress Oct4/Kdm2b induced somatic reprogramming selectively. Mechanistically, BMP-Smad pathway attenuates PRC1.1 occupation and H2AK119 ubiquitination on development genes, resulting in the release of meso-endoderm factors such as Sox17 and suppression of somatic reprogramming. These observations reveal that PRC1.1 participates in the establishment of pluripotency as well as cellular differentiation and identify BMP signal as a modulator of PRC1.1 function.
Project description:Gadd45a can enhance somatic cell reprogramming significantly. To explore the roles of Gadd45a playing in reprogramming, we performed miRNA microarray to identify miRNAs and signals pathways that regulated by Gadd45a. miRNAs expression of MEFs was measured at day8 in reprogramming. Four samples were set: MEFs infected with SKO plus Flag, MEFs infected with SKO plus Gadd45a, MEFs infected with SKOM plus Flag and MEFs infected with SKOM+Ga.
Project description:Gadd45a can enhance somatic cell reprogramming significantly. To explore the roles of Gadd45a playing in reprogramming, we performed whole genome microarray to identify genes and signals pathways that regulated by Gadd45a. Genes expression of MEFs was measured at day8 in reprogramming. Three samples were set: MEFs infected with SKO plus Flag, MEFs infected with SKO plus Gadd45a and MEFs infected with SKO plus G39A which is a negative mutant of Gadd45a.
Project description:Polycomb repressive complex 1 (PRC1) plays essential roles in cell fate determination. Recent studies have found that the composition of mammalian PRC1 is particularly varied and complicated, whereas the function of such variant PRC1 complexes on cell fate determination remains unknown. Here we show that Kdm2b, which recruits a variant PRC1 complex (PRC1.1) to CpG islands (CGIs), elevates Oct4 induced somatic reprogramming. Interaction with PRC1 is critical for Kdm2b’s promotion on the process of induced pluripotency. Furthermore, we find that bone morphogenetic proteins (BMPs) repress Oct4/Kdm2b induced somatic reprogramming selectively. Mechanistically, BMP-Smad pathway attenuates PRC1.1 occupation and H2AK119 ubiquitination on development genes, resulting in the release of meso-endoderm factors such as Sox17 and suppression of somatic reprogramming. These observations reveal that PRC1.1 participates in the establishment of pluripotency as well as cellular differentiation and identify BMP signal as a modulator of PRC1.1 function.
Project description:Somatic cells can be directly reprogrammed to pluripotency by exogenous expression of transcription factors, classically Oct4, Sox2, Klf4 and c-Myc. While distinct types of somatic cells can be reprogramed with varying efficiencies and by different modified reprogramming protocols, induced pluripotent stem cell (iPSC) induction remains inefficient and stochastic where a fraction of the cells converts into iPSCs. The nature of rate limiting barrier(s) preventing majority of cells to convert into iPSCs remains elusive. Here we show that neutralizing Mbd3, a core member of the Mbd3/NURD co-repressor and chromatin-remodeling complex, results in deterministic and synchronized reprogramming of multiple differentiated cell types to pluripotency. 100% of Mbd3 depleted mouse and human somatic cells convert into iPSCs after seven days of reprogramming factor induction. Our findings delineate a critical pathway blocking the reestablishment of pluripotency, and offer a novel platform for future dissection of epigenetic dynamics leading to iPSC formation at high resolution. Reduced representation bisulfite sequencing (RRBS) was applied to mouse iPS cells and mouse embryonic fibroblast (MEF) before and after DOX induction (initiating reprogramming by OSKM factors) from randomly selected Mbd3+/+ and Mbd3flox/- clonal cell line series. Polyclonal donor cell cultures were harvested at days 0,4 and 8 after DOX reprogramming without selection or sorting for any marker or passaging, and mapped for similarity to subcloned iPSC lines.