Transcriptomic analysis of the mature ER+ population in the mammary gland revealed enrichment for estrogen-responsive genes in the RSK2-KO compared to the wild type. Overall design: Anlaysis of gene expresison from FACS sorted EpCam-hi_CD49f+lowSca+CD49b- cells from the mammary glands of 12wk RSK2(+/+) or RSK2(-/-) mice at estrous and diestrus stages.