S-adenosylmethionine (SAM) is an important metabolite as a methyl-group donor in DNA and histone methylation, tuning regulation of gene expression. Appropriate intracellular SAM levels must be maintained, because methyltransferase reaction rates can be limited by SAM availability. In response to SAM depletion, MAT2A, which encodes a ubiquitous mammalian methionine adenosyltransferase isozyme, was upregulated through mRNA stabilization. SAM-depletion reduced N-methyladenosine (mA) in the 3' UTR of MAT2A. In vitro reactions using recombinant METTL16 revealed multiple, conserved methylation targets in the 3' UTR. Knockdown of METTL16 and the mA reader YTHDC1 abolished SAM-responsive regulation of MAT2A. Mutations of the target adenine sites of METTL16 within the 3' UTR revealed that these mAs were redundantly required for regulation. MAT2A mRNA methylation by METTL16 is read by YTHDC1, and we suggest that this allows cells to monitor and maintain intracellular SAM levels.

Primordial germ cells (PGCs), undifferentiated embryonic germ cells, are the only cells that have the ability to become gametes and to reacquire totipotency upon fertilization. It is generally understood that the development of PGCs proceeds through the expression of germ cell-specific transcription factors and characteristic epigenomic changes. However, little is known about the properties of PGCs at the metabolite and protein levels, which are directly responsible for the control of cell function. Here, we report the distinct energy metabolism of PGCs compared with that of embryonic stem cells. Specifically, we observed remarkably enhanced oxidative phosphorylation (OXPHOS) and decreased glycolysis in embryonic day 13.5 (E13.5) PGCs, a pattern that was gradually established during PGC differentiation. We also demonstrate that glycolysis and OXPHOS are important for the control of PGC reprogramming and specification of pluripotent stem cells (PSCs) into PGCs in culture. Our findings about the unique metabolic property of PGCs provide insights into our understanding of the importance of distinct facets of energy metabolism for switching PGC and PSC status.primordial germ cell | metabolome | proteome | glycolysis | oxidative phosphorylation I n mouse, germ cells first develop as primordial germ cells (PGCs) from a subset of cells in late epiblasts consisting of primed pluripotent stem cells (PSCs) that differentiate from naïve PSCs, designated primitive ectoderm or early epiblast, at around embryonic day 7.25 (E7.25) in the extraembryonic mesoderm (1). Several cytokines (2) and transcription factors (3-5) have critical roles in the emergence of PGCs. Following their initial appearance, PGCs migrate and colonize the genital ridges at ∼E10.5, subsequently exhibiting sexual differentiation at ∼E11.5. After their initial development, PGCs undergo characteristic epigenetic reprogramming, including the global reduction of histone H3 lysine 9 dimethylation (H3K9me2) and DNA methylation (6-8). As a result of the dynamic changes in gene regulation and epigenetic states that occur in the course of PGC differentiation, PGCs have developmental potential distinct from that of PSCs. Notably, PGCs show dormant totipotency, although PGCs are monopotential cells for the generation of gametes. Nonetheless, PGCs and PSCs remain closely related: both cell types share the expression of several pluripotency-associated transcription factors (9-12), and PGCs are easily reprogrammed into naïve PSCs, designated embryonic germ cells (EGCs), in culture (13,14). Therefore, the intrinsic mechanisms that control the distinct developmental potential of these two cell types are of great interest.Recent studies have focused primarily on the transcriptome and epigenome to explain the functional difference between PSCs and PGCs. However, the differences in metabolites and proteins in these cells, which may be closely linked to their distinct developmental potential, have not been examined. Recently, exhaustive analyses of metabolites, especially re...

Clostripain had a strong synergistic effect with ChNP, but not with TL. Therefore, ChNP and CP, in combination with collagenase derived from the same bacteria, may effectively increase the isolation efficiency without affecting the quality of islets.