Detection of oocyte mRNA in starfish polar bodies

The Transcriptome of a Human Polar Body Accurately Reflects Its Sibling Oocyte

“…Genes with higher levels of expression in oocytes are more reliably detectable in the sibling polar body, suggesting that a failure to identify a particular mRNA in the polar body relates to transcript levels within the oocyte that fall below a critical threshold. This finding is consistent with our previous results in both human and sea star oocytes (10,20). Our results suggest that the detection and analysis of polar body mRNA may provide insight into oocyte quality, a critical metric needed by the clinical before fertilization and transfer of the resulting embryo back into the women.…”

“…The total number of genes detected in polar bodies was highly variable between each sibling pair of oocytes and polar bodies, but the genes most abundant in oocytes were much more likely to be detected in one or more polar body samples. Furthermore, genes that were previously reported to be detected in oocytes and polar bodies by quantitative PCR (10) were present in the same rank abundance in this study. One potential concern we had for biopsying the polar body was the fear that instead of sequencing the transcriptome of the polar body, we would contaminate the sample with a cumulus cell or other accessory cell.…”

“…A potential concern was that of amplification bias, but a formal test using the Ambion Cells-to-Ct kit and quantitative PCR, which has been previously tested to linearly amplify transcripts (10), would have been prohibitively costly. However, the relative rank abundance of half a dozen previously reported transcripts (10) was recapitulated in this study using the WTA method. A second concern was the introduction of contaminants or the amplification of PCR mutations due especially to the two rounds of amplification in this study, potentially leading to mapping error.…”

“…; genes that are most abundant in the oocytes samples (dark blue) are more likely to be sampled in the polar body samples and are also found at similar expression levels. Select genes are shown on the left, including genes that have been shown to be highly expressed in oocytes (black text) (10) as well as genes significantly up-regulated in cumulus cells (green text) that were found (16). There is a high variation between the individual polar bodies (lane 3), but genes expressed at a high level in oocytes are more likely to be detected in polar bodies (black) than not (white).…”

Moving RNA moves RNA forward

“…Meiosis in oogonia generates one oocyte and three polar bodies [40]. In starfish, the copy number of RNA transcripts in the oocyte is 25-16000 folds higher than the sibling polarized bodies [41], which supports that RNA distribution influences asymmetrical division of the oocyte in meiosis. In somatic cells, mouse miR-709 is predominantly located in the nucleus and the localization pattern will rapidly change upon apoptotic stimuli [42], which provides further evidence for RNA localization's imperative effect on RNA moving.…”