Project description:Detection of genomic rearrangements from a single cell instead of a population of cells is an emerging research technique with important applications in the study of human fertility, constitutional chromosomal disorders, and tumor progression. Here, we develop a method to improve the detection of single-cell genome-wide copy number variation. Additional information about the blastomeres can be found in GSE11663.
Project description:Detection of genomic rearrangements from a single cell instead of a population of cells is an emerging research technique with important applications in the study of human fertility, constitutional chromosomal disorders, and tumor progression. Here, we develop a method to improve the detection of single-cell genome-wide copy number variation. Additional information about the blastomeres can be found in GSE11663. At this study, 14 amplified single blastomere DNA samples derived from 3-day-old and 4-day-old human embryos were analyzed by Agilent 244K array CGH. For these single cell Agilent 244K array CGH analyses: non-amplified genomic DNA extracted from the blood of a Klinefelter patient (XXY) was used as a reference sample. As a validation, the corresponding non-amplified genomic DNA samples were analyzed by 250K Nsp I SNP arrays (platform GPL3718 and GSE11663).
Project description:Single-cell whole-genome haplotyping allows simultaneous detection of haplotypes associated with monogenic diseases, chromosome copy-numbering and subsequently, has revealed mosaicism in embryos and embryonic stem cells. Methods, such as karyomapping and haplarithmisis, were deployed as a generic and genome-wide approach for preimplantation genetic testing (PGT) and are replacing traditional PGT methods. While current methods primarily rely on SNP array, we envision sequencing-based methods to become more accessible and cost-efficient. Here, we developed a novel sequencing-based methodology to haplotype and copy-number profile single cells. Following DNA amplification, genomic size and complexity is reduced through restriction enzyme digestion and DNA is genotyped through sequencing. This single-cell genotyping-by-sequencing (scGBS) is the input for haplarithmisis, an algorithm we previously developed for SNP array-based single-cell haplotyping. We established technical parameters and developed an analysis pipeline enabling accurate concurrent haplotyping and copy-number profiling of single cells. We demonstrate its value in human blastomere and trophectoderm samples as application for PGT for monogenic disorders. Furthermore, we demonstrate the method to work in other species through analyzing blastomeres of bovine embryos. Our scGBS method opens up the path for single-cell haplotyping of any species with diploid genomes and could make its way into the clinic as a PGT application.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes