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Updated: Feb 24, 2026
Transcriptome Profiling of In-Vivo Produced Bovine Pre-implantation Embryos Using Two-color Microarray Platform
Published on: January 30, 2017
MicroRNA expression in bovine preimplantation embryos
Debra K Berg1, Peter L Pfeffer1
1AgResearch Ltd, Ruakura Agricultural Centre, 10 Bisley Road, Hamilton 3214, New Zealand.
Abstract:
We profiled 98 mature microRNAs (miRNAs) using a stem-loop reverse transcription polymerase chain reaction assay array based on human miRNAs. We demonstrated that one, but not two, base-pair changes in the miRNA recognition sequence at the 3' end only marginally affected copy number estimates. Absolute levels of miRNAs were measured in matured cattle oocytes, eight-cell embryos and normal and parthenogenetic blastocysts and Day-14 trophoblast. Most miRNA concentrations were below the expected functional threshold required for effective repression of moderately to highly abundant target RNA. In oocytes and peri-embryonic genome activation embryos, miRNA 320, a member of the Dgcr8/Drosha-independent class of miRNAs, was expressed at greater than 1000 copies per embryo. miRNAs were more abundant at the eight-cell than the oocyte stage. miRNA concentrations per cell increased from the eight-cell to the blastocyst stage. Both the number of miRNA species and their expression levels were reduced in trophoblast tissue at Day 14. The parthenogenetic samples were more related in their miRNA expression profiles to each other than to their wild-type (in vitro-produced cultured) counterparts. miRNAs 299 and 323, which have been shown to be maternally expressed in other species, were also more than 4-fold overexpressed in the cattle parthenogenetic samples.
Insights
This study measured microRNA (miRNA) levels in cattle oocytes and embryos. Most miRNA concentrations were too low for effective gene repression, except for miRNA 320 in oocytes.
Area of Science:
- Reproductive biology
- Molecular biology
- Genomics
Background:
- MicroRNAs (miRNAs) are crucial regulators of gene expression.
- Understanding miRNA dynamics during early bovine development is essential for reproductive success.
Purpose of the Study:
- To quantify absolute miRNA levels in various stages of cattle oocytes and embryos.
- To assess the functional implications of miRNA concentrations for gene regulation.
- To compare miRNA profiles between normal and parthenogenetic bovine embryos.
Main Methods:
- Profiling of 98 mature human microRNAs using stem-loop reverse transcription polymerase chain reaction (RT-PCR) array.
- Absolute quantification of miRNA copy numbers in cattle oocytes, eight-cell embryos, blastocysts, and Day-14 trophoblast.
- Analysis of miRNA expression in normal versus parthenogenetic embryos.
Main Results:
- Most miRNA concentrations were below the functional threshold for effective target repression.
- miRNA 320 was highly abundant (>1000 copies/embryo) in oocytes and peri-embryonic genome activation embryos.
- miRNA abundance per cell increased from the eight-cell to blastocyst stage, but decreased in Day-14 trophoblast.
- Parthenogenetic embryos exhibited distinct miRNA expression profiles, with overexpression of miRNAs 299 and 323.
Conclusions:
- Early bovine embryos and oocytes generally possess low levels of functional miRNAs, with notable exceptions like miRNA 320.
- Developmental stage significantly impacts miRNA abundance and species diversity.
- Parthenogenesis influences miRNA expression patterns, suggesting a role in developmental abnormalities.
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