Topographical localisation of glucidic residues and their variations in the canine zona pellucida during folliculogenesis.
In the present ultrastructural study, horseradish peroxidase-labelled lectins, in conjunction with antiperoxidase antibody and protein A-gold, were used to characterise and localise the oligosaccharide sequences of zona pellucida glycoproteins at different stages of follicular development in the canine ovary. Deacetylation and sialidase digestion were also performed before lectin cytochemistry. The zona pellucida of oocytes present in unilaminar primary follicles reacts with WGA- and RCA-I-lectins. The zona pellucida of oocytes present in bilaminar and trilaminar secondary follicles displays positivity to WGA, RCA-I, Con-A, UEA-I, and sialidase/SBA. This labelling pattern persists in the zona pellucida of oocytes present in antral tertiary follicles with the exception of WGA and RCA-I reactive sites which are differently distributed throughout the zona pellucida. The topographical distribution of these carbohydrates is not uniform throughout the zona pellucida, indicating the regionalization of oligosaccharide chains within three concentric bands of the zona matrix: an inner surface close to the oocyte plasma membrane, an intermediate portion and an outer layer in contact with the follicular cells. Our results demonstrated variations in the presence and distribution of the carbohydrate residues in the canine zona pellucida during different stages of follicular growth. We also observed the presence of vesicles in both the ooplasm and granulosa cells, showing a similar lectin binding pattern to that of the zona pellucida.
Parillo
F
F
Department of Biopathological Veterinary Science, University of Perugia, via San Costanzo 4, Perugia, Italy, 06126. parillo@unipg.it
Zelli
R
R
Verini Supplizi
A
A
Fagioli
O
O
Gargiulo
A M
AM
D000818:Animals; D004285:Dogs; D004527:Egg Proteins / Q000737:chemistry*; D005260:Female; D006107:Granulosa Cells / Q000737:chemistry*; D037102:Lectins / Q000032:analysis / Q000737:chemistry; D008562:Membrane Glycoproteins / Q000737:chemistry*; D009844:Oligosaccharides / Q000032:analysis*; D006080:Ovarian Follicle / Q000254:growth & development* / Q000648:ultrastructure; D010053:Ovary; D011956:Receptors, Cell Surface / Q000737:chemistry*; D015044:Zona Pellucida / Q000737:chemistry*; D000072216:Zona Pellucida Glycoproteins
D004527:Egg Proteins; D037102:Lectins; D008562:Membrane Glycoproteins; D009844:Oligosaccharides; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins