Project description:The present study aimed at studying the rainbow trout egg transcriptome using 9152-cDNA microarrays after natural or controlled ovulation. The analysis of egg transcriptome after natural or controlled ovulation led to the identification of 26 genes. We observed that both hormonal induction and photoperiod control of ovulation induced significant changes in the egg mRNA abundance of specific genes. We demonstrate that hormonal induction of ovulation has an impact on the egg mRNA abundance of specific genes even though the resulting effects on the developmental potential of the egg is so far unknown. In addition, we also identified 1 gene exhibiting a differential mRNA abundance in eggs of varying developmental potential. Keywords: Egg quality-dependent
Project description:The present study aimed at studying the rainbow trout egg transcriptome using 9152-cDNA microarrays after natural or controlled ovulation. The analysis of egg transcriptome after natural or controlled ovulation led to the identification of 26 genes. We observed that both hormonal induction and photoperiod control of ovulation induced significant changes in the egg mRNA abundance of specific genes. We demonstrate that hormonal induction of ovulation has an impact on the egg mRNA abundance of specific genes even though the resulting effects on the developmental potential of the egg is so far unknown. In addition, we also identified 1 gene exhibiting a differential mRNA abundance in eggs of varying developmental potential. Analysis of egg transcriptome after natural ovulation (4 samples), photoperiod-controlled ovulation (14 samples), and hormonally-induced ovulation (11 samples).
Project description:Egg quality is an important aspect in rainbow trout farming. Post-ovulatory aging is one of the most important factors affecting egg quality. MicroRNAs (miRNAs) are the major regulators in various biological processes and their expression profiles could serve as reliable biomarkers for various pathological and physiological conditions. Egg samples from 32 females on day 1, day 7, and day 14 post-ovulation (D1PO, D7PO and D14PO), which had the fertilization rates of 91.8%, 73.4% and less than 50%, respectively, were collected and small RNAs isolated from these samples were subjected to deep sequencing using the Illumina platform. Six miRNAs were found to be differentially expressed between D1PO and D14PO eggs. GO analysis of the target genes of the 6 miRNAs that were down-regulated in D14PO eggs revealed significantly enriched GO terms that are related to stress response, cell death, DNA damage, ATP generation, signal transduction and transcription regulation.
Project description:Multiple mechanisms likely contribute to the increase in chromosome missegregation that leads to production of aneuploid eggs and fetuses at advanced maternal age. It is therefore considered unlikely that a single approach could prevent age-related egg aneuploidy. Here we show using three independent approaches that ovulation reduction is sufficient to prevent egg aneuploidy in aged mammals. To gain insights into the mechanism underlying the rescue in egg aneuploidy, we show that ovulation suppression correlates with retention of chromosomal Rec8-cohesin, implying that ovulations are linked to cohesin deterioration. Moreover, we discovered that ageing alters 3D chromatin organization by single-nucleus Hi-C (snHi-C). Extruded loops increase in size with age and this is retarded by ovulation reduction. We conclude that reducing ovulations leads to retention of chromosomal Rec8, which maintains interphase chromatin structure and promotes chromosome segregation and production of euploid eggs. Importantly, our data suggest that ovulation itself contributes to the maternal age effect. This work provides the first experimental evidence that progesterone treatment reduces egg aneuploidy and suggests that hormonal contraception can reduce the risk of trisomic pregnancies like Down’s syndrome at advanced maternal age.
