Noncanonical imprinting sustains embryonic development and restrains placental overgrowth.

Genomic imprinting regulates parental origin-dependent monoallelic gene expression. It is mediated by either germline differential methylation of DNA (canonical imprinting) or oocyte-derived H3K27me3 (noncanonical imprinting) in mice. Depletion of Eed, an essential component of Polycomb repressive complex 2, results in genome-wide loss of H3K27me3 in oocytes, which causes loss of noncanonical imprinting (LOI) in embryos. Although Eed maternal KO (matKO) embryos show partial lethality after implantation, it is unknown whether LOI itself contributes to the developmental phenotypes of these embryos, which makes it unclear whether noncanonical imprinting is developmentally relevant. Here, by combinatorial matKO of Xist, a noncanonical imprinted gene whose LOI causes aberrant transient maternal X-chromosome inactivation (XCI) at preimplantation, we show that prevention of the transient maternal XCI greatly restores the development of Eed matKO embryos. Moreover, we found that the placentae of Eed matKO embryos are remarkably enlarged in a manner independent of Xist LOI. Heterozygous deletion screening of individual autosomal noncanonical imprinted genes suggests that LOI of the Sfmbt2 miRNA cluster chromosome 2 miRNA cluster (C2MC), solute carrier family 38 member 4 (Slc38a4), and Gm32885 contributes to the placental enlargement. Taken together, our study provides evidence that Xist imprinting sustains embryonic development and that autosomal noncanonical imprinting restrains placental overgrowth.

Preventive effect of edaravone ointment on cyclophosphamide-chemotherapy induced alopecia.

PURPOSE: We evaluated the preventive effect of the antioxidant edaravone (EDR) on chemotherapy-induced alopecia (CIA) to improve quality of life in cancer patients. METHODS: Hair loss was induced by intraperitoneally administering cyclophosphamide (CPA, 75 mg/kg) to rats, and topically applying EDR ointment (100 mg/day) once daily for 16 days (when hair loss starts) or 21 days (just before hair growth). The rats were divided into four groups: control group (without CPA or EDR), EDR 0% group (CPA + EDR 0%), EDR 3% group (CPA + EDR 3%), and EDR 30% group (CPA + EDR 30%). The prevention of CIA was evaluated by the hair coverage score (five levels from 0 to 4). Furthermore, we measured the size of the hair follicle area and the expression levels of insulin-like growth factor (IGF)-1 mRNA in dermal papilla cells. RESULTS: The EDR 3% and EDR 30% groups exhibited higher hair coverage scores than the EDR 0% group on day 16 and day 21. On day 16, the hair follicle area in the EDR 3% and EDR 30% groups was significantly larger than that in the EDR 0% group. Furthermore, IGF-1 expression levels in the EDR 3% group were significantly higher than those in the EDR 0% group. On day 21, no significant difference was observed in hair follicle area or IGF-1 mRNA levels among the groups. CONCLUSION: Our results show that EDR administration lessened hair loss due to CPA in a dose-independent manner above doses of 3%, suggesting potential applications beside chemotherapy.

Low-Input CUT&RUN for Mouse Oocytes and Preimplantation Embryos.

Cleavage Under Target & Release Using Nuclease (CUT&RUN) enables the detection of DNA regions that are bound by a protein of interest. This method is suitable for low-input materials because of the absence of an immunoprecipitation step. However, it sometimes fails when applying it to fragile cells, such as mouse oocytes. Here we describe our low-input CUT&RUN protocol optimized for mouse oocyte and preimplantation embryo samples in which the primary antibody and protein A-MNase binding steps are completed before the cells are bound to Concanavalin A-coated magnetic beads. This modification prevents crush of oocytes and early embryos and unwanted loss of chromatin during CUT&RUN procedures.

H2AK119ub1 guides maternal inheritance and zygotic deposition of H3K27me3 in mouse embryos.

Parental epigenomes are established during gametogenesis. While they are largely reset after fertilization, broad domains of Polycomb repressive complex 2 (PRC2)-mediated formation of lysine 27-trimethylated histone H3 (H3K27me3) are inherited from oocytes in mice. How maternal H3K27me3 is established and inherited by embryos remains elusive. Here, we show that PRC1-mediated formation of lysine 119-monoubiquititinated histone H2A (H2AK119ub1) confers maternally heritable H3K27me3. Temporal profiling of H2AK119ub1 dynamics revealed that atypically broad H2AK119ub1 domains are established, along with H3K27me3, during oocyte growth. From the two-cell stage, H2AK119ub1 is progressively deposited at typical Polycomb targets and precedes H3K27me3. Reduction of H2AK119ub1 by depletion of Polycomb group ring finger 1 (PCGF1) and PCGF6-essential components of variant PRC1 (vPRC1)-leads to H3K27me3 loss at a subset of genes in oocytes. The gene-selective H3K27me3 deficiency is irreversibly inherited by embryos, causing loss of maternal H3K27me3-dependent imprinting, embryonic sublethality and placental enlargement at term. Collectively, our study unveils preceding dynamics of H2AK119ub1 over H3K27me3 at the maternal-to-zygotic transition, and identifies PCGF1/6-vPRC1 as an essential player in maternal epigenetic inheritance.