Major Proteins in Plant and Animal Eggs

In most higher plants, the female gametophyte is deeply embedded in the ovule. In an earlier work we isolated egg cells from maize ovule tissues and analyzed egg cell lysates by polyacrylamide gel electrophoresis and mass spectrometry-based proteomics technology, and identified the major protein components expressed in these cells. The identified proteins included three cytosolic enzymes for the glycolytic pathway (glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase, triosephosphate isomerase), two mitochondrial proteins (ATP synthase β-subunit and adenine nucleotide transporter), and annexin p35. Our data indicate that the plant egg cell is rich in an enzyme subset for energy metabolism. This article provides a short overview of major proteins in animal eggs, reports on major protein components of maize egg cells, and compares the major proteins between animal and plant eggs.