Figure 1.

The SORE6 Reporter Marks a Minority Cell Population that Is Enriched for Stem Cell Genes

(A) Schematic of the lentiviral stem cell reporter. AttB1,B2,B4,B5 represent AttB sites for modular Gateway recombinational cloning. SORE is the SOX2/OCT4 composite response element. For details of other elements, see Supplemental Experimental Procedures.

(B) FACS analysis showing activity of SORE6-GFP reporter in mouse ESCs with and without treatment with retinoic acid (RA) for 2 days to induce differentiation.

(C) Quantitative RT-PCR assessing the expression of stem cell transcription factors in bulk culture of breast cancer cell lines, compared with the human teratocarcinoma line NT2 as a positive control. Results are normalized to PPIA and to the lowest-expressing cell line for each gene.

(D) FACS analysis showing that the SORE6 reporter identifies a minority population in cultures of MCF10Ca1h cells. SSC, side scatter.

(E) FACS analysis showing effect on SORE6 reporter activity of overexpressing OCT4 and/or SOX2 in MCF10Ca1h cells.

(F) Quantitative RT-PCR to assess expression of master stem cell transcription factors in FACS-sorted SORE6⁺ and SORE6⁻ cells, normalized to sham-sorted cells as the control. Results are mean ± SEM (n = 3 technical replicates).

(G) Representation of SORE6⁺ cells in breast cancer cell lines of increasing malignancy. Results are mean ± SEM of three independent experiments. ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗∗p < 0.0001, Student’s t test.

See also Figure S1.