title: Null mutation of peroxisome proliferator-activated receptor-interacting protein in mammary glands causes defective mammopoiesis.
abstract: To investigate the role of nuclear receptor coactivator peroxisome proliferator-activated receptor-interacting protein (PRIP) in mammary gland development, we generated a conditional null mutation of PRIP in mammary glands. In PRIP-deficient mammary glands, the elongation of ducts during puberty was not affected, but the numbers of ductal branches were decreased, a condition that persisted long after puberty, indicating that the potential of ductal branching was impaired. During pregnancy, PRIP-deficient mammary glands exhibited decreased alveolar density. The lactating PRIP-deficient glands contained scant lobuloalveoli with many adipocytes, whereas the wild type glands were composed of virtually no adipocytes but mostly lobuloalveoli. As a result, PRIP mammary-deficient glands could not produce enough milk to nurse all the pups during lactation. The ductal branching of mammary glands in response to estrogen treatment was attenuated in PRIP mutant glands. Whereas the proliferation index was similar between wild type and PRIP-deficient glands, increased apoptosis was observed in PRIP-deficient glands. PRIP-deficient glands expressed increased amphiregulin, transforming growth factor-alpha, and betacellulin mRNA as compared with wild type glands. The differentiated function of PRIP-deficient mammary epithelial cells was largely intact, as evidenced by the expression of abundant beta-casein, whey acidic protein (WAP), and WDNM1 mRNA. We conclude that PRIP is important for normal mammary gland development.
authors.affiliation: Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611, USA.
authors.forename: Chao
authors.initials: C
authors.lastname: Qi
authors.forename: Papreddy
authors.initials: P
authors.lastname: Kashireddy
authors.forename: Yiwei Tony
authors.initials: YT
authors.lastname: Zhu
authors.forename: Sambasiva M
authors.initials: SM
authors.lastname: Rao
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Zhu
mesh_terms: D017667:Adipocytes / Q000166:cytology; D066258:Amphiregulin; D000818:Animals; D017209:Apoptosis; D066259:Betacellulin; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology*; D002364:Caseins / Q000235:genetics; D002455:Cell Division; D066255:EGF Family of Proteins; D004847:Epithelial Cells / Q000502:physiology; D004967:Estrogens / Q000008:administration & dosage / Q000502:physiology; D005260:Female; D015870:Gene Expression; D006023:Glycoproteins / Q000235:genetics; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D007774:Lactation / Q000502:physiology; D008321:Mammary Glands, Animal / Q000033:anatomy & histology / Q000254:growth & development*; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008894:Milk Proteins / Q000235:genetics; D009154:Mutation; D056918:Nuclear Receptor Coactivators; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012741:Sexual Maturation; D016211:Transforming Growth Factor alpha / Q000235:genetics; D000067816:Whey Proteins
chemical_list: D066258:Amphiregulin; C587849:Areg protein, mouse; D066259:Betacellulin; C587852:Btc protein, mouse; D002352:Carrier Proteins; D002364:Caseins; D066255:EGF Family of Proteins; D004967:Estrogens; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008894:Milk Proteins; C405683:Ncoa6 protein, mouse; D056918:Nuclear Receptor Coactivators; D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha; D000067816:Whey Proteins