{"owner": "ArrayExpress Uploader", "pop_total": 0, "id": 5709, "factors": [{"GSE16380GSM410920": {}}, {"GSE16380GSM410921": {}}, {"GSE16380GSM410922": {}}, {"GSE16380GSM410923": {}}, {"GSE16380GSM410924": {}}, {"GSE16380GSM410925": {}}, {"GSE16380GSM410926": {}}, {"GSE16380GSM410927": {}}], "ownerprofile_id": "arrayexpress_sid", "platform": 6, "summary_wrapped": "CCAAT/enhancer binding protein beta (C/EBPb) is a member of a family of highly conserved transcription factors that regulates numerous...", "pubmed_id": 20054865, "geo_gse_id": "E-GEOD-16380", "owner_profile": "/profile/8773/arrayexpressuploader", "factor_count": 0, "sample_count": 8, "tags": ["basal", "breast", "breast cancer", "cancer", "cell", "compartment", "gland", "luminal", "protein", "stem cell"], "lastmodified": "Dec.12, 2014", "is_default": false, "geo_gds_id": "", "slug": "gene-expression-analyses-of-cebpb-knockout-in-stem", "geo_id_plat": "E-GEOD-16380_A-AFFY-45", "name": "Gene expression analyses of C/EBPb knockout in stem/progenitor cell populations", "created": "Nov.11, 2014", "summary": "CCAAT/enhancer binding protein beta (C/EBPb) is a member of a family of highly conserved transcription factors that regulates numerous genes involved in proliferation and differentiation in a variety of tissues.  C/EBPb is deregulated in human breast cancer and germline deletion of this gene results in multiple defects in mammary gland development.  We hypothesized that C/EBPb regulates mammary stem cell self-renewal, maintenance and/or differentiation through the regulation of multiple target genes that coordinate mammary gland development.  Utilizing both a germline knockout mouse model and a conditional knockout strategy, we demonstrated that mammosphere formation was significantly decreased in C/EBPb-deficient mammary epithelial cells (MECs).  The ability of C/EBPb-deleted MECs to regenerate the mammary gland in vivo was severely impaired when transplanted at limiting dilution.  Furthermore, serial transplantation of C/EBPb-null mammary tissue resulted in decreased outgrowth potential when compared to wildtype, and an early senescence phenotype.  Flow cytometric analysis revealed that C/EBPb-null MECs contain a lower frequency of repopulating stem cells accompanied by an increase in committed, differentiated luminal cells as compared to wildtype. Microarray analysis of stem/progenitor cell populations was performed and revealed an alteration in cell fate specification in C/EBPb-null glands, exemplified by the aberrant expression of basal markers in the luminal cell compartment.  Collectively, our studies demonstrate that C/EBPb is a critical regulator of mammary stem cell differentiation, and an important determinant of luminal cell fate specification. Experiment Overall Design: To identify potential signaling pathways regulated by C/EBPb in stem/progenitor cells, microarray analysis was performed on two stem/progenitor cell subpopulations.  For this analysis, subpopulations defined by LIN-CD24+CD29hi and LIN-CD24hiCD29lo were FACS sorted from wildtype and germline C/EBPb-/- glands, and RNA was isolated from each group.", "source": "http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-16380", "species": "mouse", "sample_source": "http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-16380/samples/"}