Fig. 1

ErbB3 loss decreases expansion of the mammary epithelium during pregnancy. a Erbb3 mRNA expression is maximal during late puberty in mice. Data and plot extracted and generated from the National Center for Biotechnology Information Gene Expression Omnibus dataset GDS2843 using the probe set 96771_at. Details of the study published in [60]. Red columns indicate the single channel transformed counts, while blue data points indicate the percentile rank of Erbb3 transcripts within the samples. b–e Mammary glands harvested from 12–15-week-old mice at 16 d.p.c. and L1. N = 9 per time point. Representative images are shown, original magnification is 400×. b IHC detection of ErbB3. c IF staining of K8 (red) and ErbB3 (green). Sections were counterstained with DAPI. d Histological sections stained with hematoxylin and eosin. e Quantitation of epithelial density in randomly selected 200× fields. Using digital images, epithelial areas were circumscribed to generate a closed polygon to generate an automated calculation of the polygon area. Each data point represents the average of three randomly chosen fields per sample; midlines are the average of all biological replicates ± SD. P values calculated using Student’s unpaired two-way t test. f Litters were normalized to eight pups each, then pups were weighed postnatally at days 3 and 10. Each data point represents the average pup weight of a single litter; midlines are the average of all litters within the group. N = 12 litters. Student’s unpaired, two-way t test. dpc days post coitus, Lact d lactation day (Color figure online)