Involvement of the linker histone H1Foo in the regulation of oogenesis.

In Brief: In oocytes, chromatin structure is loosened during their growth, which seems to be essential for the establishment of competence to accomplish the maturation and further development after fertilization. This paper shows that a linker histone variant, H1foo, is involved in the formation of loosened chromatin structure in growing oocytes.

Abstract: During oogenesis, oocytes show a unique mode of division and gene expression patterns.

Minor zygotic gene activation is essential for mouse preimplantation development.

In mice, transcription initiates at the mid-one-cell stage and transcriptional activity dramatically increases during the two-cell stage, a process called zygotic gene activation (ZGA). Associated with ZGA is a marked change in the pattern of gene expression that occurs after the second round of DNA replication. To distinguish ZGA before and after the second-round DNA replication, the former and latter are called minor and major ZGA, respectively.

Identification of the small molecule compound which induces hepatic differentiation of human mesenchymal stem cells.

Human mesenchymal stem cells (MSCs) are expected to have utility as a cell source in regenerative medicine. Because we previously reported that suppression of the Wnt/β-catenin signal enhances hepatic differentiation of human MSCs, we synthesized twenty-three derivatives of small molecule compounds originally reported to suppress the Wnt/β-catenin signal in human colorectal cancer cells. We then screened these compounds for their ability to induce hepatic differentiation of human UE7T-13 MSCs.

Characterization of gene expression in mouse embryos at the 1-cell stage.

In mice, transcription from the zygotic genome is initiated at the mid-1-cell stage after fertilization. Although a recent high-throughput sequencing (HTS) analysis revealed that this transcription occurs promiscuously throughout almost the entire genome in 1-cell stage embryos, a detailed investigation of this process has yet to be conducted using protein-coding genes. Thus, the present study utilized previous RNA sequencing (RNAseq) data to determine the characteristics and regulatory regions of genes transcribed at the 1-cell stage.

The first murine zygotic transcription is promiscuous and uncoupled from splicing and 3' processing.

Initiation of zygotic transcription in mammals is poorly understood. In mice, zygotic transcription is first detected shortly after pronucleus formation in 1-cell embryos, but the identity of the transcribed loci and mechanisms regulating their expression are not known. Using total RNA-Seq, we have found that transcription in 1-cell embryos is highly promiscuous, such that intergenic regions are extensively expressed and thousands of genes are transcribed at comparably low levels.

Global gene silencing is caused by the dissociation of RNA polymerase II from DNA in mouse oocytes.

As mouse oocytes approach maturity, a global repression of gene transcription occurs. Here, we investigated the involvement of RPB1, the largest subunit of RNA polymerase II (RNAP II), in the regulation of this transcriptional silencing mechanism. Using BrUTP to follow transcription in an in vitro run-on assay, we observed an abrupt decrease in transcriptional activity when oocytes reached their full size (approximately 80 µm).