title: MicroRNA expression and regulation in the uterus during embryo implantation in rat.
abstract: Embryo implantation is a complex initial step in establishment of a successful pregnancy. Many mRNAs have been shown to be differentially expressed in the rat uterus during embryo implantation. However, the expression profiles of microRNAs (miRNAs), a key post-transcriptional regulator of gene expression, in the rat uterus between the pre-receptive and receptive phases are still unknown. Here, an miRNA microarray was used to examine differential expression of miRNAs in the rat uterus between the pre-receptive and receptive phases. Twenty-eight miRNAs were up-regulated and 29 miRNAs were down-regulated at least twofold during the receptive phase in rat uterus; these results were confirmed by Northern blotting. miR-29a was only highly expressed in rat uterus during the implantation period, and activation of delayed implantation and artificial decidualization enhanced the miR-29a level. Further investigation revealed that both the pro-apoptotic factor genes Bak1 and Bmf and the anti-apoptotic factor gene Bcl-w are targets of miR-29a. There was weak binding between miR-29a and the 3' UTR of the anti-apoptotic factor gene Mcl1. Over-expression of miR-29a inhibited the late apoptosis of endometrial stromal cells, which may be due to the stronger binding capacity between miR-29a and the 3' UTR of pro-apoptotic factors than that between miR-29a and the 3' UTR of anti-apoptotic factors. Collectively, miR-29a plays an important role during embryo implantation by regulating both pro-apoptotic and anti-apoptotic factors. miR-29a may predominantly bind pro-apoptotic factors, leading to inhibition of cell apoptosis.
authors: Reproductive and Genetic Center of National Research Institute for Family Planning, Beijing, China; Graduate School, Peking Union Medical College, Beijing, China.
authors: Hong-Fei
authors: HF
authors: Xia
authors: Xiao-Hua
authors: XH
authors: Jin
authors: Zong-Fu
authors: ZF
authors: Cao
authors: Yi
authors: Y
authors: Hu
authors: Xu
authors: X
authors: Ma
mesh_terms: D020413:3' Untranslated Regions; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D010064:Embryo Implantation; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000235:genetics / Q000378:metabolism; D011247:Pregnancy; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D048868:Adaptor Proteins, Signal Transducing; C494774:Bak1 protein, rat; C491072:Bcl2l2 protein, rat; C486656:Bmf protein, rat; C526366:MIRN29 microRNA, rat; C579093:Mcl1 protein, rat; D035683:MicroRNAs; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D050998:bcl-2 Homologous Antagonist-Killer Protein
keywords: Bcl-2 family; embryo implantation; miR-29a; miRNAs; rat uterus