Pregnancy-Induced Noncoding RNA (PINC) Associates with Polycomb Repressive Complex 2 and Regulates Mammary Epithelial Differentiation
(A) RT-PCR shows multiple splice forms of mPINC1.0 and mPINC1.6 are expressed during mammary gland development. Primers designed to the extreme ends of mPINC1.0 and mPINC1.6 were used to amplify cDNA from mammary gland developmental stages. (w Vir.: weeks old virgin, d Preg.: days pregnancy, d Lac.: days lactation, d Inv.: days involution). PCR products were sequenced and found to be new splice forms of mPINC, including a new splice variant of mPINC1.6 called DCR2, for deleted conserved region 2. (B) Schematic diagram of mPINC exonic structure. Black boxes represent exons that are always included, grey boxes are sometimes included and clear boxes are never included. Nucleotide length is indicated above each exon along with black lines that overlap the most conserved regions of the PINC locus, CR1 and CR2. Exon 6 sometimes has an additional 24 nucleotides at the 3′ end in the mPINC1.0 and mPINC1.6 splice forms. This alternative splice site does not correlate with the inclusion/exclusion of any particular exon and its function is unknown. (C) qPCR shows mPINC is highest during late pregnancy and early involution. Mammary glands were harvested from 3 female Balb/c mice for each stage (V: adult virgin, dP: days pregnant, dL: days lactation, dI: days involution). Target genes were normalized to Actb and set relative to levels in the virgin mammary gland. (D) mPINC expression is most abundant in the mammary gland. Tissues were harvested from three 10 week old virgin Balb/c female mice and testis, epididymis, and prostate was harvested from three 12 week old male Balb/c mice. ND indicates tissues in which mPINC was not detected by qPCR. Target genes were normalized to Actb and set relative to levels in the lung.