Fig. 6. Mammary epithelial expression of MYC from D12.5-D15.5 of pregnancy promotes premature Stat5 hyperactivation. MTB and MTB/TOM mice induced with doxycycline from D12.5-D15.5 were sacrificed at 24-hour intervals from D12.5 pregnancy-D1PP. Mammary protein lysates were separated by SDS-PAGE and blotted onto nitrocellulose membranes. Blots were probed with antibodies specific to Y694/Y699 phosphorylated Stat5a/b, total Stat5a/b, and ß-tubulin. Results are representative of experiments performed on two separate sets of animals.