Messenger RNA expression of Pabpnl1 and Mbd3l2 genes in oocytes and cleavage embryos

Objective

To identify genes specifically expressed in mammalian oocytes using an in silico subtraction, and to characterize the mRNA patterns of selected genes in oocytes, embryos, and adult tissues.

Design

Comparison between oocyte groups and between early embryo stages.

Setting

Laboratories of embryo manipulation and molecular biology from Departamento de Genética (FMRP) and Departamento de Ciências Básicas (FZEA) - University of São Paulo.

Sample(s)

Oocytes were collected from slaughtered cows for measurements, in vitro fertilization, and in vitro embryo culture. Somatic tissue, excluding gonad and uterus tissue, was collected from male and female cattle.

Main Outcome Measure(s)

Messenger RNA levels of poly(A)-binding protein nuclear-like 1 (Pabpnl1) and methyl-CpG–binding domain protein 3–like 2 (Mbd3l2).

Result(s)

Pabpnl1 mRNA was found to be expressed in oocytes, and Mbd3l2 transcripts were present in embryos. Quantification of Pabpnl1 transcripts showed no difference in levels between good- and bad-quality oocytes before in vitro maturation (IVM) or between good-quality oocytes before and after IVM. However, Pabpnl1 transcripts were not detected in bad-quality oocytes after IVM. Transcripts of the Mbd3l2 gene were found in 4-cell, 8-cell, and morula-stage embryos, with the highest level observed in 8-cell embryos.

Conclusion(s)

Pabpnl1 gene expression is restricted to oocytes and Mbd3l2 to embryos. Different Pabpnl1 mRNA levels in oocytes of varying viability suggest an important role in fertility involving the oocyte potential for embryo development.

Key Words: Bovine, embryo, gene expression