<i>Mcs1a</i> affects rat mammary epithelial cell (RMEC) growth and differentiation.

<p>A) Results of the limiting-dilution RMEC transplantation assay. Graphed is the percentage of transplant sites with an outgrowth versus the number of RMECs transplanted. Vertical bars represent lower and upper limits of a 95%-confidence interval for a proportion. Outgrowth potential of RMECs from the susceptible congenic control (susc.; light grey) and <i>Mcs1a</i> resistant congenic (res.; dark grey) line (lines W4 and W5 combined) is not significantly different. B) Pseudocolor dot plots from a susceptible congenic control sample, representing the gating strategy used to enrich for clonogenic luminal RMECs using cell sorting on the BD FACS Aria. CD31–CD45− RMECs were divided into luminal and basal cells based on CD24 and CD29 expression (left panel). Based on staining with anti-CD61 and peanut lectin (PNL), the clonogenic luminal cell population (CD45–CD31-CD24hiCD29medCD61+PNLhi; <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003549#pgen.1003549.s003" target="_blank">Figure S3</a>) was selected for Matrigel assays (right panel). C) Graphed is the average (+/− sem) number of spherical mammary colonies formed in Matrigel assays plating 10,000 clonogenic RMECs sorted from the susceptible congenic control (n = 12) and <i>Mcs1a</i> resistant congenic line (n = 10; line W4 only). In the lower panel, a representative picture of a spherical mammary colony in a methylene blue-stained Matrigel is shown. Significantly different colony-forming ability (P<0.05) is indicated by an asterisk.