Building comparative gene expression databases for the mouse preimplantation embryo using a pipeline approach to UniGene

PlagueKD: a knowledge graph-based plague knowledge database

Plague has been confirmed as an extremely horrific international quarantine infectious disease attributed to Yersinia pestis. It has an extraordinarily high lethal rate that poses a serious hazard to human and animal lives. With the deepening of research, there has been a considerable amount of literature related to the plague that has never been systematically integrated. Indeed, it makes researchers time-consuming and laborious when they conduct some investigation. Accordingly, integrating and excavating plague-related knowledge from considerable literature takes on a critical significance. Moreover, a comprehensive plague knowledge base should be urgently built. To solve the above issues, the plague knowledge base is built for the first time. A database is built from the literature mining based on knowledge graph, which is capable of storing, retrieving, managing and accessing data. First, 5388 plague-related abstracts that were obtained automatically from PubMed are integrated, and plague entity dictionary and ontology knowledge base are constructed by using text mining technology. Second, the scattered plague-related knowledge is correlated through knowledge graph technology. A multifactor correlation knowledge graph centered on plague is formed, which contains 9633 nodes of 33 types (e.g. disease, gene, protein, species, symptom, treatment and geographic location), as well as 9466 association relations (e.g. disease-gene, gene-protein and disease-species). The Neo4j graph database is adopted to store and manage the relational data in the form of triple. Lastly, a plague knowledge base is built, which can successfully manage and visualize a large amount of structured plague-related data. This knowledge base almost provides an integrated and comprehensive plague-related knowledge. It should not only help researchers to better understand the complex pathogenesis and potential therapeutic approaches of plague but also take on a key significance to reference for exploring potential action mechanisms of corresponding drug candidates and the development of vaccine in the future. Furthermore, it is of great significance to promote the field of plague research. Researchers are enabled to acquire data more easily for more effective research. Database URL: http://39.104.28.169:18095/.

Identification of mouse 8-cell embryo stage-specific genes by Digital Differential Display

Preimplantation development is critical for successful implantation and pregnancy. In the mouse preimplantation embryo, the first event of morphological and cellular differentiation is established during polarization and compaction at the 8-cell stage. The considerable cell surface and cytoplasmic changes and formation of different populations of cells at the 8-cell stage are fundamentally important for the development of all organisms. To determine genes that are specifically expressed at this crucial stage of embryo development and also to shed light on the different mechanisms that could be of importance during embryo development, we investigated mouse 8-cell and 4-cell embryo stage-specific genes using Digital Differential Display (DDD). The 8-cell stage-specific genes were sorted according to their ontology data from the Database for Annotation, Visualization and Integrated Discovery (DAVID), which outlines possible roles for the genes expressed at the 8-cell stage. This study highlights how online tools can be used to identify genes involved in embryo development. Identification of the 8-cell embryo stage-specific genes would open new opportunities for understanding molecular networks during the mid-preimplantation gene activation. Using bioinformatic tools, such as Digital Differential Display and DAVID, it will be possible to identify genes expressed at the 8-cell stage that are likely to be involved in mammalian preimplantation embryo development. Our results may provide a new foundation for molecular control at the onset of embryonic development in mammals, and should be of interest to the scientific community.

An integrated approach for the systematic identification and characterization of heart-enriched genes with unknown functions

Background

High throughput techniques have generated a huge set of biological data, which are deposited in various databases. Efficient exploitation of these databases is often hampered by a lack of appropriate tools, which allow easy and reliable identification of genes that miss functional characterization but are correlated with specific biological conditions (e.g. organotypic expression).

Results

We have developed a simple algorithm (DGSA = Database-dependent Gene Selection and Analysis) to identify genes with unknown functions involved in organ development concentrating on the heart. Using our approach, we identified a large number of yet uncharacterized genes, which are expressed during heart development. An initial functional characterization of genes by loss-of-function analysis employing morpholino injections into zebrafish embryos disclosed severe developmental defects indicating a decisive function of selected genes for developmental processes.

Conclusion

We conclude that DGSA is a versatile tool for database mining allowing efficient selection of uncharacterized genes for functional analysis.

Characterization of tissue-specific mbu-3 gene expression in the mouse central nervous system

Mbu-3 is a novel mouse brain unigene that was identified by digital differential display. In this study, expression of the gene was chased through developmental stages and the protein product was identified in the brain. The cDNA sequence was 3,995-bp long and contained an ORF of 745 AA. Database searches revealed that the chicken SST273 gene containing LRR- and Ig-domain was an mbu-3 orthologue. Tissue specificity for the gene was examined in embryos and in brains at post-natal and adult stages. During the embryonic stages, mbu-3 was localized to the central nervous system in the brain and spinal cord. In the early post-natal stages, the gene was evenly expressed in the brain. However, with aging, expression was confined to specific regions, particularly the hippocampus. The protein was approximately 95 kDa as determined by Western blot analysis of brain extracts.

Determination of microRNAs in mouse preimplantation embryos by microarray

Expression profile of microRNA (miRNA) in mouse oocytes and preimplantation embryos has been revealed by a novel high throughput microarray assay. A total of 97 (43 "new" and 54 known) including mouse, human, and predicted miRNAs have been discovered in the preimplantation mouse embryos which can be classified into developmental stage-dependent groups and non-stage-dependent group according to the statistical analysis of the expression patterns. Potential gene targets of each group of miRNAs are estimated by TargetsScan system and significantly changed signaling pathways and biological processes underlying these gene targets are searched by PANTHER classification system between the stage-dependent miRNAs and the non-stage-dependent miRNAs. Expression of some miRNAs is confirmed by reverse transcriptase-polymerase chain reaction. It is shown that dynamic synthesis and degradation of miRNAs coexists in the preimplantation development of mouse embryos. However, the overall quantity of miRNAs and percentage of the stage-dependent miRNAs increase as the preimplantation embryos develop.