Bovine Male-Enhanced Antigen(Mea) Gene Is Expressed in Early Embryos as Revealed by the Reverse Transcriptase-Polymerase Chain Reaction(RT-PCR).

The male-enhanced antigen (Mea) gene, the product of which was reactive with the H-Y antibody, was isolated from a bovine testicular cDNA library, and its expression in bovine early embryos was analyzed by the reverse transcriptase-polymerase chain reaction (RT-PCR). Analyses using diluted mRNA from blastocyst embryos suggested that it could detect the Mea transcripts from just a few blastocyst cells. Expression of the Mea gene was not detected at the 2-cell stage, but it was detected in 8-cell embryos to hatched blastocysts. When the sex of one half of a bisected blastocyst was determined by the usual PCR using bovine Y-chromosome specific primers and the other half by RT-PCR, all blastocysts having Y-chromosome sequences were found to express the Mea gene. Most embryos without Y specific sequences did not express the Mea gene, but a small fraction of them unexpectedly did. These findings indicate that the Mea gene could be useful for sexing early embryos by RT-PCR and especially to identify female embryos.