Oviduct-Embryo Interactions in Cattle: Two-Way Traffic or a One-Way Street? [RNA-Seq]

The objective of this study was to examine the effect of the presence of a single or multiple embryo(s) on the transcriptome of the bovine oviduct. In Experiment 1, cyclic (non-bred, n = 6) and pregnant (artificially inseminated, n = 11) heifers were slaughtered on Day 3 after estrus, and the ampulla and isthmic regions of the oviduct ipsilateral to the corpus luteum were separately flushed. Oviductal epithelial cells from the isthmus region, in which all oocytes/embryos were located, were snap-frozen for microarray analysis. In Experiment 2, heifers were divided into cyclic (non-bred, n = 6) or pregnant (multiple embryo transfer, n = 10) groups. In vitro-produced presumptive zygotes were transferred endoscopically to the ipsilateral oviduct on Day 1.5 post estrus (n = 50 zygotes per heifer). Heifers were slaughtered on Day 3 and oviductal isthmus epithelial cells were recovered for RNA sequencing. Microarray analysis in Experiment 1 failed to detect any difference in the transcriptome of the oviductal isthmus induced by the presence of a single embryo. In Experiment 2, following multiple embryo transfer, RNA sequencing revealed 278 differentially expressed genes of which 123 were up- and 155 were down-regulated in pregnant heifers. Most of the down-regulated genes were related to immune function. Overall design: Transcriptional profiles of oviductal isthmus epithelial cells from cyclic and pregnant heifers were generated by sequencing of total RNA on the Illumina HiSeq 2500 platform

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Maillo V, Gaora PÓ, Forde N, Besenfelder U, Havlicek V, Burns GW, Spencer TE, Gutierrez-Adan A, Lonergan P, Rizos D