Amy Shore, Ph.D.
Revealing the Function of a Noncoding RNA that is Upregulated in the Pregnant Mammary Gland
An early full term pregnancy has been suggested to reduce the risk of developing breast cancer by as much as 50%. This protective effect can be reproduced in a rodent model by treatment with estrogen and progesterone (E+P) for 21 days to mimic pregnancy, which greatly reduces carcinogen-induced tumorigenesis compared to untreated controls.
Our laboratory previously identified differentially expressed genes between E+P-treated and age-matched virgin mammary glands of Wistar-Firth rats and found a novel gene, which we call PINC for pregnancy-induced noncoding RNA, that is upregulated in the E+P-treated mammary gland. Further studies revealed seven alternatively spliced, polyadenylated forms of PINC in the rat. In-situ hybridization showed PINC expression in the epithelial cells of the lobuloalveoler structures of the pregnant mammary gland, as well as in the surviving epithelial cells of the regressed lobules following involution. A highly homologous gene is expressed in the mouse that is also alternatively spliced to give rise to mPINC 1.0(1.0Kb) and mPINC 1.6(1.6Kb). Like PINC, expression of both forms is also upregulated during pregnancy. Initial in-vitro studies using siRNA to knockdown expression of each form in HC11 cells, a mammary epithelial cell line derived from a mid-pregnant mouse, suggest that mPINC 1.0 functions as a survival factor and mPINC 1.6 may play a role in cell cycle regulation.
Our current hypothesis is that different splice forms of PINC play distinct roles during the cyclical development of the post-pubertal mammary gland resulting in changes in cell fate in the surviving cells of the involuted mammary gland following pregnancy. It is thought that this population of cells, which has been shown to exhibit progenitor properties, is left behind to expand in subsequent pregnancies. These cells are able to survive the massive burst of apoptosis that occurs during involution and they show a reduced proliferative response to a carcinogen challenge.
We propose that these unique, persistent effects of an early pregnancy may be the result of chromatin modifications through an epigenetic process involving PINC, a suggested role for noncoding RNAs. To determine the function of mPINC in the mammary gland, the expression of the individual splice forms will be examined through the various postpubertal stages including, pregnancy, lactation, and involution. Also, proteins that bind mPINC will be identified using MS2-MBP pull-downs and mass spectrometry. Since mPINC is expresssed in several tissues, including the embryo, several complementary approaches will be employed to study the function of mPINC: 1) regulatable shRNAi constructs will be used in mammary gland reconstitution experiments, and 2) transgenic mice will be generated using a novel shRNAi expression system.
- Joined: May 2005
- Position: Postdoctoral Fellow
- Degree: Ph.D., Baylor College of Medicine 2012 & BA University of Virginia, 1998
- Awards: Department of Defense BCRP Predoctoral Fellowship
Shore, AN, Kabotyanski, E.B., Roarty, K., Smith, M.A., Zhang, Y, Creighton, C.J., Dinger, M.E. and Rosen, J M. (2012) Pregnancy-induced Noncoding RNA(PINC) Associates with Polycomb Repressive Complex 2 and Regulates Mammary Epithelial Differentiation. PLoS Genetics 8:e1002840.
Ginger MR, Shore AN, Contreras A, Rijnkels M, Miller J, Gonzalez-Rimbau MF, and Rosen JM.A noncoding RNA is a potential marker of cell fate during mammary gland development. PNAS 2006 April 11; 103(15):5781-5786 [PDF] [Supp. Fig 1] [Supp. Fig 2] [Supp. Fig 3] [Supp. Fig 4] [Supp. Fig 5][Supp. Fig 6] [Supp. Methods]
Acharya KK, Govind CK, Shore AN, Stoler MH, Reddi PP. cis-requirement for the maintenance of round spermatid-specific transcription.Dev Biol. 2006 Jul 15;295(2):781-90.
Reddi PP, Shore AN, Shapiro JA, Anderson A, Stoler MH, Acharya KK.Spermatid-specific promoter of the SP-10 gene functions as an insulator in somatic cells.Dev Biol. 2003 Oct 1;262(1):173-82.
Wright PW, Bolling LC, Calvert ME, Sarmento OF, Berkeley EV, Shea MC, Hao Z, Jayes FC, Bush LA, Shetty J, Shore AN, Reddi PP, Tung KS, Samy E, Allietta MM, Sherman NE, Herr JC, Coonrod SA. ePAD, an oocyte and early embryo-abundant peptidylarginine deiminase-like protein that localizes to egg cytoplasmic sheets. Dev Biol. 2003 Apr 1;256(1):73-88.
Hao Z, Stoler MH, Sen B, Shore A, Westbrook A, Flickinger CJ, Herr JC, Coonrod SA.TACC3 expression and localization in the murine egg and ovary. Mol Reprod Dev. 2002 Nov;63(3):291-9.
Bush LA, Herr JC, Wolkowicz M, Sherman NE, Shore A, Flickinger CJ. A novel asparaginase-like protein is a sperm autoantigen in rats.Mol Reprod Dev. 2002 Jun;62(2):233-47.
Reddi PP, Shore AN, Acharya KK, Herr JC. Transcriptional regulation of spermiogenesis: insights from the study of the gene encoding the acrosomal protein SP-10. J Reprod Immunol. 2002 Jan;53(1-2):25-36.