In homeostasis of adult vertebrate tissues, stem cells are thought to self-renew by infrequent and asymmetric divisions that generate another stem cell daughter and a progenitor daughter cell committed to differentiate. This model is based largely on in vivo invertebrate or in vitro mammal studies. Here we examine the dynamic behaviour of adult hair follicle stem cells in their normal setting by employing mice with repressible H2B-GFP expression to track cell divisions and Cre inducible mice to perform long-term single cell lineage tracing. We provide direct evidence for the infrequent stem cell division model in intact tissue. Moreover, we find that differentiation of progenitor cells occurs at different times and tissue locations than self-renewal of stem cells. Distinct fates of differentiation or self-renewal are assigned to individual cells in a temporal-spatial manner. We propose that large clusters of tissue stem cells behave as populations, whose maintenance involves unidirectional daughter-cell fate decisions.
Distinct self-renewal and differentiation phases in the niche of infrequently dividing hair follicle stem cells.
Specimen part
View SamplesThis data series was used for two separate studies. The initial study was aimed to idenify expression changes brought about by the Cecr2Gt45Bic mutation during neural closure. The study included two different strains, BALB/cCrl in which Cecr2GT45Bic shows a neural tube defect phenotype and FVB/N in which Cecr2Gt45Bic does not manifest neural closure defects. The second was to idenify strain specific expression differences present during neural closure of the mouse embryo between BALB/cCrl and FVB/N in order to identify candidate modifiers of the Cecr2Gt45Bic neural tube defect. Relevant abstracts are included below.
Strain-specific modifier genes of Cecr2-associated exencephaly in mice: genetic analysis and identification of differentially expressed candidate genes.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Differential roles of Sall4 isoforms in embryonic stem cell pluripotency.
Specimen part, Cell line
View SamplesMurine embryonic stem cells (ESCs) are defined by continuous self-renewal and pluripotency. A diverse repertoire of protein isoforms arising from alternative splicing are expressed in ES cells without defined biological roles. Sall4, a transcription factor essential for pluripotency, exists as two isoforms (Sall4a and Sall4b). By genome-wide location analysis, we have determined that Sall4b, and not Sall4a, binds preferentially to highly expressed loci in ES cells. Sall4a and Sall4b binding sites are distinguished by both epigenetic marks at target loci and their clustering with binding sites of other pluripotency factors. When ESCs expressing a single isoform of Sall4 are generated, Sall4b alone could maintain the pluripotent state, although it could not completely suppress all differentiation markers. Sall4a and Sall4b collaborate in maintenance of the pluripotent state, but play distinct roles. Our work is novel in establishing such isoform-specific differences in ES cells.
Differential roles of Sall4 isoforms in embryonic stem cell pluripotency.
Specimen part, Cell line
View SamplesEpithelial-mesenchymal transition (EMT) has been linked to cancer progression and metastatic propensity. The 4T1 tumor is a clinically relevant model of spontaneous breast cancer metastasis. Here we characterize 4T1-derived cell lines for EMT, in vitro invasiveness and in vivo metastatic ability. Contrary to expectations, the 67NR cells, which form primary tumors but fail to metastasize, express vimentin and N-cadherin, but not E-cadherin. 4T1 cells, however, express E-cadherin, are highly migratory and invasive, and metastasize to multiple sites. The 66cl4 metastatic cells display mixed epithelial and mesenchymal markers, but are less migratory and invasive than 67NR cells. These findings demonstrate that the metastatic ability of breast cancer cells does not correlate with genotypic and phenotypic properties of EMT per se, and suggest that other processes may govern metastatic capability. Gene expression analysis also has not identified differences in EMT markers, but has identified several candidate genes that may influence metastatic ability.
Epithelial-mesenchymal transition (EMT) is not sufficient for spontaneous murine breast cancer metastasis.
Sex, Specimen part
View SamplesAnalyzing the kenetics of alveolar macrophage turnover after human lung transplantation and identifying protein and transcriptional differences between donor and recipient-derived alveolar macrophages Overall design: Bulk RNA sequencing performed from FACS sorted donor and recipient-derived alveolar macrophages derived from the bronchoalveolar lavage of lung transplant recipients, defined as CD45+, Live, lineage negative, CD64+CD206+ cells.
Rate of recipient-derived alveolar macrophage development and major histocompatibility complex cross-decoration after lung transplantation in humans.
Specimen part, Subject
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