Cortical progenitor biology: key features mediating proliferation versus differentiation.

The cerebral cortex is a highly organized structure whose development depends on diverse progenitor cell types, namely apical radial glia, intermediate progenitors, and basal radial glia cells, which are responsible for the production of the correct neuronal output. In recent years, these progenitor cell types have been deeply studied, particularly basal radial glia and their role in cortical expansion and gyrification. We review here a broad series of factors that regulate progenitor behavior and daughter cell fate.

Prdm16 is crucial for progression of the multipolar phase during neural differentiation of the developing neocortex.

The precise control of neuronal migration and morphological changes during differentiation is essential for neocortical development. We hypothesized that the transition of progenitors through progressive stages of differentiation involves dynamic changes in levels of mitochondrial reactive oxygen species (mtROS), depending on cell requirements. We found that progenitors had higher levels of mtROS, but that these levels were significantly decreased with differentiation.

Cell-cycle-independent transitions in temporal identity of mammalian neural progenitor cells.

During cerebral development, many types of neurons are sequentially generated by self-renewing progenitor cells called apical progenitors (APs). Temporal changes in AP identity are thought to be responsible for neuronal diversity; however, the mechanisms underlying such changes remain largely unknown. Here we perform single-cell transcriptome analysis of individual progenitors at different developmental stages, and identify a subset of genes whose expression changes over time but is independent of differentiation status.

Identification and characterization of the zosA gene involved in copper uptake in Bacillus subtilis 168.

DL-Penicillamine, a copper-specific metal chelator, remarkably suppressed the growth of Bacillus subtilis 168 when added to a synthetic medium under Cu(2+) limitation. DNA microarray and screening of 2,602 knockout mutants showed that the zosA gene was de-repressed in the presence of 0.1% dl-penicillamine, and that the zosA mutant was sensitive to dl-penicillamine medium.

Soybean extracts increase cell surface ZIP4 abundance and cellular zinc levels: a potential novel strategy to enhance zinc absorption by ZIP4 targeting.

Dietary zinc deficiency puts human health at risk, so we explored strategies for enhancing zinc absorption. In the small intestine, the zinc transporter ZIP4 functions as an essential component of zinc absorption. Overexpression of ZIP4 protein increases zinc uptake and thereby cellular zinc levels, suggesting that food components with the ability to increase ZIP4 could potentially enhance zinc absorption via the intestine.

Establishment of trophoblast stem cells under defined culture conditions in mice.

The inner cell mass (ICM) and trophoblast cell lineages duet early embryonic development in mammals. After implantation, the ICM forms the embryo proper as well as some extraembryonic tissues, whereas the trophoectoderm (TE) exclusively forms the fetal portion of the placenta and the trophoblast giant cells. Although embryonic stem (ES) cells can be derived from ICM in cultures of mouse blastocysts in the presence of LIF and/or combinations of small-molecule chemical compounds, and the undifferentiated pluripotent state can be stably maintained without use of serum and feeder cells, defined culture conditions for derivation and maintenance of undifferentiated trophoblast stem (TS) cells have not been established.

Nuclear transfer in the mouse oocyte.

The nuclear transfer (NT) technique in the mouse has enabled us to generate cloned mice and to establish NT embryonic stem (ntES) cells. Direct nuclear injection into mouse oocytes with a piezo impact drive unit can aid in the bypass of several steps of the original cell fusion procedure. It is important to note that only the NT approach can reveal dynamic and global modifications in the epigenome without using genetic modification as well as generating live animals from single cells.

Early ontogenic origin of the hematopoietic stem cell lineage.

Several lines of evidence suggest that the adult hematopoietic system has multiple developmental origins, but the ontogenic relationship between nascent hematopoietic populations under this scheme is poorly understood. In an alternative theory, the earliest definitive blood precursors arise from a single anatomical location, which constitutes the cellular source for subsequent hematopoietic populations. To deconvolute hematopoietic ontogeny, we designed an embryo-rescue system in which the key hematopoietic factor Runx1 is reactivated in Runx1-null conceptuses at specific developmental stages.

A new class of rhodamine luminophores: design, syntheses and aggregation-induced emission enhancement.

A new class of rhodamine luminophores, 3',3''-bis(oxospiroisobenzofuran)-3,7-bis(dialkylamino)benzopyrano-xanthene derivatives (ABPX), have been successfully developed. The emission behavior of ABPX series is directly opposite to the concentration quenching of conventional rhodamine dyes. ABPX series exhibit aggregation-induced emission enhancement (AIEE).

Lunatic fringe potentiates Notch signaling in the developing brain.

Notch signaling is essential for the self-renewal of mammalian neural progenitor cells. A variety of mechanisms modulate Notch signaling to balance the self-renewal and differentiation of progenitor cells. Fringe is a major Notch regulator and promotes or suppresses Notch signaling, depending on the Notch ligands.

Use of lectins to enrich mouse ES-derived retinal progenitor cells for the purpose of transplantation therapy.

Using the mouse ES cell line with green fluorescent protein knocked-in at the Rx locus (Rx-KI ES cell), we previously showed that photoreceptors can be efficiently obtained in defined culture conditions by enriching Rx-positive retinal progenitor cells. We aimed to explore a protocol applicable for non-Rx-labeled stem cell lines for subsequent enrichment of retinal photoreceptor precursors for transplantation. The Rx-KI ES cell line was differentiated according to the serum-free suspension conditions with serum-free suspension/Dkk1/LeftyA/serum/activin method (SFEB/DLFA) described previously.

A signaling principle for the specification of the germ cell lineage in mice.

Specification of the germ cell lineage is vital to development and heredity. In mice, the germ cell fate is induced in pluripotent epiblast cells by signaling molecules, yet the underlying mechanism remains unknown. Here we demonstrate that germ cell fate in the epiblast is a direct consequence of Bmp4 signaling from the extraembryonic ectoderm (ExE), which is antagonized by the anterior visceral endoderm (AVE).

Rostral paraxial mesoderm regulates refinement of the eye field through the bone morphogenetic protein (BMP) pathway.

The eye field is initially a large single domain at the anterior end of the neural plate and is the first indication of optic potential in the vertebrate embryo. During the course of development, this domain is subject to interactions that shape and refine the organogenic field. The action of the prechordal mesoderm in bisecting this single region into two bilateral domains has been well described, however the role of signalling interactions in the further restriction and refinement of this domain has not been previously characterised.

Specification of the germ cell lineage in mice.

Specification of the germ cell lineage is fundamental in development and heredity. In mice, and presumably in all mammals, germ cell fate is not an inherited trait from the egg, but is induced in pluripotent epiblast cells by signaling molecules. Recent studies are beginning to uncover the signaling requirements and key transcriptional regulators for the specification of the germ cell lineage in mice, as well as the distinct properties that the specified germ cells acquire uniquely.

Functional analysis of male mouse haploid germ cells of various differentiation stages: early and late round spermatids are functionally equivalent in producing progeny.

Spermiogenesis is a complex process consisting of three main phases: the round, elongating, and elongated spermatid phases. Although the germ cells acquire a haploid set of paternal chromosomes after meiosis, how functional these male haploid germ cells are as male gametes at various differentiation stages has remained unclear. We selectively injected specific steps of haploid male germ cells into oocytes and assessed the function of the zygotes.

Single-cell gene profiling defines differential progenitor subclasses in mammalian neurogenesis.

Cellular diversity of the brain is largely attributed to the spatial and temporal heterogeneity of progenitor cells. In mammalian cerebral development, it has been difficult to determine how heterogeneous the neural progenitor cells are, owing to dynamic changes in their nuclear position and gene expression. To address this issue, we systematically analyzed the cDNA profiles of a large number of single progenitor cells at the mid-embryonic stage in mouse.

Critical function of Prdm14 for the establishment of the germ cell lineage in mice.

Specification of germ cell fate is fundamental in development and heredity. Recent evidence indicates that in mice, specification of primordial germ cells (PGCs), the common source of both oocytes and spermatozoa, occurs through the integration of three key events: repression of the somatic program, reacquisition of potential pluripotency and ensuing genome-wide epigenetic reprogramming. Here we provide genetic evidence that Prdm14, a PR domain-containing transcriptional regulator with exclusive expression in the germ cell lineage and pluripotent cell lines, is critical in two of these events, the reacquisition of potential pluripotency and successful epigenetic reprogramming.

FGF signaling regulates cytoskeletal remodeling during epithelial morphogenesis.

Changes in the cytoskeletal architecture underpin the dynamic changes in tissue shape that occur during development. It is clear that such changes must be coordinated so that individual cell behaviors are synchronized; however, the mechanisms by which morphogenesis is instructed and coordinated are unknown. After its induction in non-neural ectoderm, the inner ear undergoes morphogenesis, being transformed from a flat ectodermal disk on the surface of the embryo to a hollowed sphere embedded in the head.

Complex genome-wide transcription dynamics orchestrated by Blimp1 for the specification of the germ cell lineage in mice.

Specification of germ cell fate is fundamental in development. With a highly representative single-cell microarray and rigorous quantitative PCR analysis, we defined the genome-wide transcription dynamics that create primordial germ cells (PGCs) from the epiblast, a process that exclusively segregates them from their somatic neighbors. We also analyzed the effect of the loss of Blimp1, a key transcriptional regulator, on these dynamics.

Single-cell cDNA high-density oligonucleotide microarray analysis: detection of individual cell types and properties in complex biological processes.

Gene expression analyses at the single-cell level have been identifying genes that are expressed and play key roles in distinct populations of cells constituting a wide variety of tissues in multicellular organisms. With the development of high-density oligonucleotide microarray platforms covering whole genome transcript information from many organisms, the demand has grown for methods of quantitative global mRNA amplification from a small number of cells, especially single cells. This article reviews briefly some of the pioneering studies in the detection of genes expressed in single cells of interest, with emphasis on the quantitative performance of the amplification methodologies employed.

Nuclear transfer alters the DNA methylation status of specific genes in fertilized and parthenogenetically activated mouse embryonic stem cells.

Recent cloning technology has been demonstrated successfully using nuclear transfer (NT) techniques to generate embryonic stem (ES) cells. Mice can be cloned from adult somatic cells or ES cells by NT, and such cloned embryos can be used to establish new NT-ES cell lines. However, ES cells derived from parthenogenetic embryos show epigenetic disorders and low potential for normal differentiation unless used to produce subsequent generations of NT-ES lines.

Cellular dynamics associated with the genome-wide epigenetic reprogramming in migrating primordial germ cells in mice.

We previously reported that primordial germ cells (PGCs) in mice erase genome-wide DNA methylation and histone H3 lysine9 dimethylation (H3K9me2), and instead acquire high levels of tri-methylation of H3K27 (H3K27me3) during their migration, a process that might be crucial for the re-establishment of potential totipotency in the germline. We here explored a cellular dynamics associated with this epigenetic reprogramming. We found that PGCs undergo erasure of H3K9me2 and upregulation of H3K27me3 in a progressive, cell-by-cell manner, presumably depending on their developmental maturation.

Global single-cell cDNA amplification to provide a template for representative high-density oligonucleotide microarray analysis.

We describe here a protocol for the representative amplification of global mRNAs from typical single mammalian cells to provide a template for high-density oligonucleotide microarray analysis. A single cell is lysed in a tube without purification and first-strand cDNAs are synthesized using a poly(dT)-tailed primer. Unreacted primer is specifically eliminated by exonuclease treatment and second strands are generated with a second poly(dT)-tailed primer after poly(dA) tailing of the first-strand cDNAs.