[Premenstrual syndrome (PMS)].
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Diagnosis, Differential↗
Biomedical subjects
Toshio Hamatani
Publications and source records attributed to Toshio Hamatani.
Global gene expression profiling of preimplantation embryos.
Preimplantation development is marked by four major events: the transition of maternal transcripts to zygotic transcripts, compaction, the first lineage differentiation into inner cell mass and trophectoderm, and implantation. The scarcity of the materials of preimplantation embryos, both in size (diameter < 100 microm) and in quantity (only a few to tens of oocytes from each ovulation), has hampered molecular analysis of preimplantation embryos. Recent progress in RNA amplification methods and microarray platforms, including genes unique to preimplantation embryos, allow us to apply global gene expression profiling to the study of preimplantation embryos. Our gene expression profiling during preimplantation development revealed the distinctive patterns of maternal RNA degradation and embryonic gene activation, including two major transient waves of de novo transcription. The first wave corresponds to zygotic genome activation (ZGA). The second wave, mid-preimplantation gene activation (MGA), contributes dramatic morphological changes during late preimplantation development. Further expression profiling of embryos treated with inhibitors of transcription or translation revealed that the translation of maternal RNA is required for the initiation of ZGA, suggesting a cascade of gene activation from maternal RNA/protein sets to ZGA gene sets and thence to MGA gene sets. To date, several reports of microarray experiments using mouse and human preimplantation embryos have been published. The identification of a large number of genes and multiple signaling pathways involved at each developmental stage by such global gene expression profiling accelerates understanding of molecular mechanisms underlining totipotency/pluripotency and programs of early mammalian development.
Animals↗
Age-associated alteration of gene expression patterns in mouse oocytes.
Decreasing oocyte competence with maternal aging is a major factor in human infertility. To investigate the age-dependent molecular changes in a mouse model, we compared the expression profiles of metaphase II oocytes collected from 5- to 6-week-old mice with those collected from 42- to 45-week-old mice using the NIA 22K 60-mer oligo microarray. Among approximately 11,000 genes whose transcripts were detected in oocytes, about 5% (530) showed statistically significant expression changes, excluding the possibility of global decline in transcript abundance. Consistent with the generally accepted view of aging, the differentially expressed genes included ones involved in mitochondrial function and oxidative stress. However, the expression of other genes involved in chromatin structure, DNA methylation, genome stability and RNA helicases was also altered, suggesting the existence of additional mechanisms for aging. Among the transcripts decreased with aging, we identified and characterized a group of new oocyte-specific genes, members of the human NACHT, leucine-rich repeat and PYD-containing (NALP) gene family. These results have implications for aging research as well as for clinical ooplasmic donation to rejuvenate aging oocytes.
Aging↗
Global gene expression analysis identifies molecular pathways distinguishing blastocyst dormancy and activation.
Delayed implantation (embryonic diapause) occurs when the embryo at the blastocyst stage achieves a state of suspended animation. During this period, blastocyst growth is very slow, with minimal or no cell division. Nearly 100 mammals in seven different orders undergo delayed implantation, but the underlying molecular mechanisms that direct this process remain largely unknown. In mice, ovariectomy before preimplantation ovarian estrogen secretion on day 4 of pregnancy initiates blastocyst dormancy, which normally lasts for 1-2 weeks by continued progesterone treatment, although blastocyst survival decreases with time. An estrogen injection rapidly activates blastocysts and initiates their implantation in the progesterone-primed uterus. Using this model, here we show that among approximately 20,000 genes examined, only 229 are differentially expressed between dormant and activated blastocysts. The major functional categories of altered genes include the cell cycle, cell signaling, and energy metabolic pathways, particularly highlighting the importance of heparin-binding epidermal growth factor-like signaling in blastocyst-uterine crosstalk in implantation. The results provide evidence that the two different physiological states of the blastocyst, dormancy and activation, are molecularly distinguishable in a global perspective and underscore the importance of specific molecular pathways in these processes. This study has identified candidate genes that provide a scope for in-depth analysis of their functions and an opportunity for examining their relevance to blastocyst dormancy and activation in numerous other species for which microarray analysis is not available or possible due to very limited availability of blastocysts.
Animals↗
Dynamics of global gene expression changes during mouse preimplantation development.
Understanding preimplantation development is important both for basic reproductive biology and for practical applications including regenerative medicine and livestock breeding. Global expression profiles revealed and characterized the distinctive patterns of maternal RNA degradation and zygotic gene activation, including two major transient waves of de novo transcription. The first wave corresponds to zygotic genome activation (ZGA); the second wave, named mid-preimplantation gene activation (MGA), precedes the dynamic morphological and functional changes from the morula to blastocyst stage. Further expression profiling of embryos treated with inhibitors of transcription, translation, and DNA replication revealed that the translation of maternal RNAs is required for the initiation of ZGA. We propose a cascade of gene activation from maternal RNA/protein sets to ZGA gene sets and thence to MGA gene sets. The large number of genes identified as involved in each phase is a first step toward analysis of the complex gene regulatory networks.
Animals↗
Aging of oocyte, ovary, and human reproduction.
We review age-related changes in the ovary and their effect on female fertility, with particular emphasis on follicle formation, follicle dynamics, and oocyte quality. The evidence indicates that the developmental processes leading to follicle formation set the rules determining follicle quiescence and growth. This regulatory system is maintained until menopause and is directly affected in at least some models of premature ovarian failure (POF), most strikingly in the Foxl2 mouse knockout, a model of human POF with monogenic etiology (blepharophimosis/ptosis/epicanthus inversus syndrome). Several lines of evidence indicate that if the ovarian germ cell lineage maintains regenerative potential, as recently suggested in the mouse, a role in follicle dynamics for germ stem cells, if any, is likely indirect or secondary. In addition, age-related variations in oocyte quality in animal models suggest that reproductive competence is acquired progressively and might depend on parallel growth and differentiation of follicle cells and stroma. Genomewide analyses of the mouse oocyte transcriptome have begun to be used to systematically investigate the mechanisms of reproductive competence that are altered with aging. Investigative and therapeutic strategies can benefit from considering the role of continuous interactions between follicle cells and oocytes from the beginning of histogenesis to full maturation.
Aging↗
Transcriptome analysis of mouse stem cells and early embryos.
Understanding and harnessing cellular potency are fundamental in biology and are also critical to the future therapeutic use of stem cells. Transcriptome analysis of these pluripotent cells is a first step towards such goals. Starting with sources that include oocytes, blastocysts, and embryonic and adult stem cells, we obtained 249,200 high-quality EST sequences and clustered them with public sequences to produce an index of approximately 30,000 total mouse genes that includes 977 previously unidentified genes. Analysis of gene expression levels by EST frequency identifies genes that characterize preimplantation embryos, embryonic stem cells, and adult stem cells, thus providing potential markers as well as clues to the functional features of these cells. Principal component analysis identified a set of 88 genes whose average expression levels decrease from oocytes to blastocysts, stem cells, postimplantation embryos, and finally to newborn tissues. This can be a first step towards a possible definition of a molecular scale of cellular potency. The sequences and cDNA clones recovered in this work provide a comprehensive resource for genes functioning in early mouse embryos and stem cells. The nonrestricted community access to the resource can accelerate a wide range of research, particularly in reproductive and regenerative medicine.
Animals↗
In situ-synthesized novel microarray optimized for mouse stem cell and early developmental expression profiling.
Applications of microarray technologies to mouse embryology/genetics have been limited, due to the nonavailability of microarrays containing large numbers of embryonic genes and the gap between microgram quantities of RNA required by typical microarray methods and the miniscule amounts of tissue available to researchers. To overcome these problems, we have developed a microarray platform containing in situ-synthesized 60-mer oligonucleotide probes representing approximately 22,000 unique mouse transcripts, assembled primarily from sequences of stem cell and embryo cDNA libraries. We have optimized RNA labeling protocols and experimental designs to use as little as 2 ng total RNA reliably and reproducibly. At least 98% of the probes contained in the microarray correspond to clones in our publicly available collections, making cDNAs readily available for further experimentation on genes of interest. These characteristics, combined with the ability to profile very small samples, make this system a resource for stem cell and embryogenomics research.
Animals↗
Expression and subcellular distribution of the active form of c-Src tyrosine kinase in differentiating human endometrial stromal cells.
Decidual growth factors and locally produced cytokines are thought to activate specific phosphorylation signalling pathway(s), thereby eliciting a variety of decidual functions. We have previously reported the activation of c-Src tyrosine kinase during ovarian steroid-induced decidualization of cultured human endometrial stromal cells. As chicken c-Src is known to be activated upon dephosphorylation of tyrosine 527 (Y527, corresponding to Y530 in human), we here employed a monoclonal antibody, clone 28, directed against the active form of human c-Src whose Y530 is dephosphorylated, and investigated whether c-Src became dephosphorylated at Y530 and thereby activated during decidualization. We found that the active form of c-Src was up-regulated and demonstrated increased kinase activity during in-vitro decidualization. Immunohistochemistry revealed that decidual cells in early pregnancy decidua were intensely stained with clone 28 when compared with the stromal cells in the non-pregnant endometrium. Moreover, the active form of c-Src translocated from a perinuclear region to the cytoplasm upon decidualization. Thus, the Y530 dephosphorylation, kinase activation, and subcellular translocation of c-Src may be intracellular signalling events associated with decidualization in vivo as well as in vitro.
CSK Tyrosine-Protein Kinase↗
Assembly, verification, and initial annotation of the NIA mouse 7.4K cDNA clone set.
A set of 7407 cDNA clones (NIA mouse 7.4K) was assembled from >20 cDNA libraries constructed mainly from early mouse embryos, including several stem cell libraries. The clone set was assembled from embryonic and newborn organ libraries consisting of ~120,000 cDNA clones, which were initially re-arrayed into a set of ~11,000 unique cDNA clones. A set of tubes was constructed from the racks in this set to prevent contamination and potential mishandling errors in all further re-arrays. Sequences from this set (11K) were analyzed further for quality and clone identity, and high-quality clones with verified identity were re-arrayed into the final set (7.4K). The set is freely available, and a corresponding database was built to provide comprehensive annotation for those clones with known identity or homology, and has been made available through an extensive Web site that includes many link-outs to external databases and analysis servers.
Animals↗
The NIA cDNA project in mouse stem cells and early embryos.
A catalog of mouse genes expressed in early embryos, embryonic and adult stem cells was assembled, including 250000 ESTs, representing approximately 39000 unique transcripts. The cDNA libraries, enriched in full-length clones, were condensed into the NIA 15 and 7.4K clone sets, freely distributed to the research community, providing a standard platform for expression studies using microarrays. They are essential tools for studying mammalian development and stem cell biology, and to provide hints about the differential nature of embryonic and adult stem cells.
Animals↗