EP300 promotes lung cancer cell proliferation by regulating the oncogenic transcription of Hippo-YAP signaling pathway.

The transcriptional activation function of YAP in cancer development has been widely studied. However, the underlying regulatory mechanisms remain largely unknown. In this study, we found that EP300, one histone acetyltransferase, interacted with YAP and was recruited into the phase separated condensates of YAP. Transcriptomic analysis revealed substantial alterations in gene expression upon EP300 depletion, with downregulated genes associated with cancer progression and Hippo-YAP pathway. Notably, disruption of EP300 inhibited the transcriptional activation of YAP and reduced the binding of H3K27ac on YAP target oncogenes in Hippo pathway. Moreover, depletion of EP300 effectively inhibited YAP-driven tumor growth. Taken together, these results indicate that EP300 contributes to lung cancer progression by promoting the oncogenic transcription of YAP through H3K27ac, which suggests that YAP-EP300 axis may be potential therapeutic targets for lung cancer treatment.

Generation of stable integration-free pig induced pluripotent stem cells under chemically defined culture condition.

Genome integration-free pig induced pluripotent stem cells (iPSCs) bring tremendous value in pre-clinical testing of regenerative medicine, as well as conservation and exploitation of endangered or rare local pig idioplasmatic resources. However, due to a lack of appropriate culture medium, efficient induction and stable maintenance of pig iPSCs with practical value remains challenging. Here, we established an efficient induction system for exogenous gene-independent iPSCs under chemically defined culture condition previously used for generation of stable pig pre-gastrulation epiblast stem cells (pgEpiSCs). WNT suppression was found to play an essential role in establishment of exogenous gene-independent iPSCs. Strikingly, stable integration-free pig iPSCs could be established from pig somatic cells using episomal vectors in this culture condition. The iPSCs had pluripotency features and transcriptome characteristics approximating pgEpiSCs. More importantly, this induction system may be used to generate integration-free iPSCs from elderly disabled rare local pig somatic cells and the iPSCs could be gene-edited and used as donor cells for nuclear transfer. Our results provide novel insights into potential applications for genetic breeding of livestock species and pre-clinical evaluation of regenerative medicine.

scm6A-seq reveals single-cell landscapes of the dynamic m6A during oocyte maturation and early embryonic development.

N6-methyladenosine (m6A) has been demonstrated to regulate RNA metabolism and various biological processes, including gametogenesis and embryogenesis. However, the landscape and function of m6A at single cell resolution have not been extensively studied in mammalian oocytes or during pre-implantation. In this study, we developed a single-cell m6A sequencing (scm6A-seq) method to simultaneously profile the m6A methylome and transcriptome in single oocytes/blastomeres of cleavage-stage embryos. We found that m6A deficiency leads to aberrant RNA clearance and consequent low quality of Mettl3Gdf9 conditional knockout (cKO) oocytes. We further revealed that m6A regulates the translation and stability of modified RNAs in metaphase II (MII) oocytes and during oocyte-to-embryo transition, respectively. Moreover, we observed m6A-dependent asymmetries in the epi-transcriptome between the blastomeres of two-cell embryo. scm6A-seq thus allows in-depth investigation into m6A characteristics and functions, and the findings provide invaluable single-cell resolution resources for delineating the underlying mechanism for gametogenesis and early embryonic development.

METTL3-mediated mRNA N6-methyladenosine is required for oocyte and follicle development in mice.

Proper follicle development is very important for the production of mature oocytes, which is essential for the maintenance of female fertility. This complex biological process requires precise gene regulation. The most abundant modification of mRNA, N6-methyladenosine (m6A), is involved in many RNA metabolism processes, including RNA splicing, translation, stability, and degradation. Here, we report that m6A plays essential roles during oocyte and follicle development. Oocyte-specific inactivation of the key m6A methyltransferase Mettl3 with Gdf9-Cre caused DNA damage accumulation in oocytes, defective follicle development, and abnormal ovulation. Mechanistically, combined RNA-seq and m6A methylated RNA immunoprecipitation sequencing (MeRIP-seq) data from oocytes revealed, that we found METTL3 targets Itsn2 for m6A modification and then enhances its stability to influence the oocytes meiosis. Taken together, our findings highlight the crucial roles of mRNA m6A modification in follicle development and coordination of RNA stabilization during oocyte growth.

[Characterization of D-lactate dehydrogenase isozymes from a D-lactic acid producing bacterium Sporolactobacillus inulinus].

Objective: Sporolactobacillus inulinus, a typical homofermentative lactic acid bacterium, is an efficient D-lactic acid producer. Various environment factors affect the productivity of S. inulinus. Glucokinase, phosphofructokinase, pyruvate kinase and lactic dehydrogenase are the key enzymes of D-lactic acid production from glucose by S. inulinus. The characteristics of these enzymes are important in controlling and regulating the fermentation process. According to the genome bioinformatics analysis of S. inulinus CASD, three putative D-lactate dehydrogenases were identified, among which the bifunctional protein had been reported. In this study, we provided insights into the characteristics of the other two D-lactate dehydrogenase isozymes. Methods: S. inulinus Y2-8 genome was used as the template to amplify D-lactate dehydrogenase gene (dldh) and D-isomer specific 2-hydroxyacid dehydrogenase gene (dhdh). The two recombinant strains E-pET-28a/dldh and E-pET-28a/dhdh were constructed for enzyme expression. Both recombinants DLDH and DHDH could convert pyruvic acid into D-lactic acid. Results: Enzymes expressed by recombinant strains were purified by Ni-NTA chromatography. The apparent molecular mass of DLDH was approximately 37 kDa by SDS-PAGE analysis, and DLDH showed a high affinity to pyruvate with the Km value of (0.58±0.04) mmol/L. The optimal reaction temperature and pH for DLDH was 35℃ and 6.5, respectively. The apparent molecular mass of DHDH was approximately 39 kDa, and the Km of DHDH toward pyruvate was (1.70±0.08) mmol/L. The optimum catalysis temperature and pH of DHDH were 30℃ and 7.5, respectively. Conclusion: According to the Km and optimal reaction pH, DLDH was suggested as the main catalyst in formation D-lactic acid from pyruvate during the fermentation. The enzymatic properties would contribute to the regulation of the fermentation of S. inulinus.