Proteomic analysis of the chicken egg vitelline membrane

Abstract

The avian vitelline membrane (VM) is a multilayered proteinaceous structure separating egg white from yolk. The innermost layer of the VM, deposited onto the oocyte plasma membrane in the ovary, corresponds to the mammalian zona pellucida (ZP). The outer layer is produced in the infundibulum, the first section of the oviduct. Using high-throughput, high-end LC-MS(n) 137 proteins were identified, only 13 of which were known previously to be components of the VM. Depending on the washing protocol, two largely overlapping, but not identical, sets of identified proteins were produced from water-washed and salt-washed VMs. Most of the components of the VM were known previously from other egg compartments, such as, for instance, the egg white proteins lysozyme C, ovalbumin, ovotransferrin, and ovomucin. Specific components of the VM not identified previously in other egg compartments included eight ZP proteins, oviductin protease, and two ATPases. The vitelline outer membrane protein (VMO) VMO II was identified as beta-defensin-11. The list of VM proteins presented in this report is by far the most comprehensive dataset available at present and complements proteomic analyses of chicken egg compartments published previously.

Three-dimensional NMR Structure of Hen Egg Gallin (Chicken Ovodefensin) Reveals a New Variation of the β-Defensin Fold

“…Gallin is a chicken cysteine-rich cationic peptide previously identified in the chicken egg white and vitelline membrane by proteomic approaches (26,27). Its antibacterial activities against the Gram-negative bacteria E. coli were recently demonstrated (34).…”

“…Proteomic analyses of the chicken egg revealed the presence of AvBDs, especially AvBD9, AvBD10, and AvBD11, identified in the egg yolk, eggshell, and eggshell/egg white/vitelline membrane, respectively (26 -29). In addition to these AvBDs, another cysteine-rich and cationic peptide of 41 residues (4731.68 Da), named gallin, was also detected in the hen egg white and vitelline membrane (27,30). This peptide was named gallin because of its sequence homology with meleagrin and cygnin, two peptides present in the egg whites of turkey (Meleagris) and swan (Cygnus), respectively (31,32).…”

Scientific Opinion on the public health risks of table eggs due to deterioration and development of pathogens

“…This membrane is made up of three layers: the inner layer formed in the ovary; a continuous intermediate layer; and the outer layer deposited in the oviduct (Mann, 2008). The outer surface of the vitelline membrane in fresh eggs is composed of fibres connected to the chalaziferous layer.…”

“…Ovomucin appears to form the skeleton of the outer layer, but especially lysozyme is responsible for its integrity. Another protein isolated from the outer layer is the vitelline membrane outer layer protein II (VMOII) (Kido et al, 1992;Mann, 2008). The functions of VMOI and VMO II are unknown.…”

“…The functions of VMOI and VMO II are unknown. The inner layer consists largely of the glycoproteins GPI, GPII and GPIII (Mann, 2008). The vitelline membrane also contains numerous enzymes whose functions are not entirely elucidated, including several ATPases and proteases (Mann, 2008).…”