Personne : Caballero, Julieta
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L'Alliance Boviteq, Université Laval
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- PublicationAccès libreExploring the function of long non-coding RNA in the development of bovine early embryos(CSIRO publishing, 2014-12-04) Gilbert, Isabelle; Caballero, Julieta; Fournier, Éric; Scantland, Sara; Gagné, Dominique; Robert, Claude; Macaulay, AngusNow recognised as part of the cellular transcriptome, the function of long non-coding (lnc) RNA remains unclear. Previously, we found that some lncRNA molecules in bovine embryos are highly responsive to culture conditions. In view of a recent demonstration that lncRNA may play a role in regulating important functions, such as maintenance of pluripotency, modification of epigenetic marks and activation of transcription, we sought evidence of its involvement in embryogenesis. Among the numerous catalogued lncRNA molecules found in oocytes and early embryos of cattle, three candidates chosen for further characterisation were found unexpectedly in the cytoplasmic compartment rather than in the nucleus. Transcriptomic survey of subcellular fractions found these candidates also associated with polyribosomes and one of them spanning transzonal projections between cumulus cells and the oocyte. Knocking down this transcript in matured oocytes increased developmental rates, leading to larger blastocysts. Transcriptome and methylome analyses of these blastocysts showed concordant data for a subset of four genes, including at least one known to be important for blastocyst survival. Functional characterisation of the roles played by lncRNA in supporting early development remains elusive. Our results suggest that some lncRNAs play a role in translation control of target mRNA. This would be important for managing the maternal reserves within which is embedded the embryonic program, especially before embryonic genome activation.
- PublicationRestreintThe use of adenosine to inhibit oocyte meiotic resumption in Bos taurus during pre-IVM and its potential to improve oocyte competence(Elsevier Inc., 2019-10-07) Vigneault, Christian; Caballero, Julieta; Richard, François J.; Sirard, Marc-André; Blondin, Patrick.One of the major challenges of artificial reproductive technologies is to develop new methods for pro-ducing greater numbers of embryos. An oocyte fosters the ability to develop into an embryo beforeoocyte meiotic resumption. The aim of the present study was to assess the effect of adenosine (ADO), apurine nucleoside found in follicularfluid, on the inhibition of oocyte meiotic resumption and theproduction of blastocysts. The results showed the efficacy of ADO to inhibit oocyte meiotic resumption.The use of ADO (3 mM) during a pre-in vitro maturation (pre-IVM) culture period of 6 h resulted in asignificant increase (p<0.05) of blastocysts compared to control conditions with no pre-IVM cultureperiod. No effect on the percentage of cleavage was observed. The effect of adenosine on blastocyst yieldwas time- and concentration-dependent with an optimum effect at 3 mM for 6 h. Supplementing theADO pre-IVM culture medium with estradiol, follicle-stimulating hormone, progesterone, epidermalgrowth factor, insulin-like growth factor-2 or reelin did not improve the blastocyst yield. Transcriptionalanalyses of ADO-treated cumulus cells revealed that NRP1, RELN, MAN1A1, THRA and GATM were up-regulated. Finally, bioinformatic analysis identified mitochondrial function as the top canonicalpathway affected by ADO. This opens up new opportunities for further investigations.
- PublicationRestreintThe gametic synapse : RNA transfer to the bovine oocyte(Oxford University Press, 2014-10-01) Gilbert, Isabelle; Caballero, Julieta; Tossou, Prudencio; Khandjian, Edward William; Macaulay, Angus; Richard, François J.; Barreto, Rodrigo; Clarke, Hugh James; Robert, Claude; Fournier, Éric; Sirard, Marc-André; Hyttel, P.Even after several decades of quiescent storage in the ovary, the female germ cell is capable of reinitiating transcription to build the reserves that are essential to support early embryonic development. In the current model of mammalian oogenesis, there exists bilateral communication between the gamete and the surrounding cells that is limited to paracrine signaling and direct transfer of small molecules via gap junctions existing at the end of the somatic cells' projections that are in contact with the oolemma. The purpose of this work was to explore the role of cumulus cell projections as a means of conductance of large molecules, including RNA, to the mammalian oocyte. By studying nascent RNA with confocal and transmission electron microscopy in combination with transcript detection, we show that the somatic cells surrounding the fully grown bovine oocyte contribute to the maternal reserves by actively transferring large cargo, including mRNA and long noncoding RNA. This occurrence was further demonstrated by the reconstruction of cumulus-oocyte complexes with transfected cumulus cells transferring a synthetic transcript. We propose selective transfer of transcripts occurs, the delivery of which is supported by a remarkable synapselike vesicular trafficking connection between the cumulus cells and the gamete. This unexpected exogenous contribution to the maternal stores offers a new perspective on the determinants of female fertility.