Karolinska Institutet

About: Karolinska Institutet is a education organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Population & Cancer. The organization has 46212 authors who have published 121142 publications receiving 6008130 citations.

Characterization of the single-cell transcriptional landscape by highly multiplex RNA-seq

Abstract: Our understanding of the development and maintenance of tissues has been greatly aided by large-scale gene expression analysis. However, tissues are invariably complex, and expression analysis of a tissue confounds the true expression patterns of its constituent cell types. Here we describe a novel strategy to access such complex samples. Single-cell RNA-seq expression profiles were generated, and clustered to form a two-dimensional cell map onto which expression data were projected. The resulting cell map integrates three levels of organization: the whole population of cells, the functionally distinct subpopulations it contains, and the single cells themselves-all without need for known markers to classify cell types. The feasibility of the strategy was demonstrated by analyzing the transcriptomes of 85 single cells of two distinct types. We believe this strategy will enable the unbiased discovery and analysis of naturally occurring cell types during development, adult physiology, and disease.

Identification of human chromosomes by DNA-binding fluorescent agents

Abstract: The distribution of DNA along metaphase chromosomes that are not excessively contracted can be visualized in the fluorescence microscope with the aid of fluorescent DNA-binding agents. Additional, characteristic details in the fluorescence patterns are obtained with fluorochromes that bind preferentially to certain chromosomal regions. The highly fluorescent alkylating agent quinacrine mustard (QM) effects discrete, fluorescent labeling of both plant and mammalian metaphase chromosomes, presumably by selective binding to guanine residues in DNA, and is also capable of intercalation in the DNA double helix. Chromosome regions fluorescing particularly strongly with QM have been demonstrated in human metaphase chromosomes 3, 13–15 and Y. A convenient measuring technique has been developed for the rapid and accurate recording of fluorescence patterns in human metaphase chromosomes. These photoelectric recordings of the fluorescence patterns contain far greater detail than can be seen by the human eye. The fluorescence patterns described are based on measurements of about 1,000 human metaphase chromosomes. This new technique of determining fluorescence patterns in human chromosomes should be particularly valuable for the identification of chromosomes 4–5 and the individual types in the 6–12 group. Individual, typical patterns also occur within the groups 13–15, 17–18, and 21–22.