Localization of plasminogen in the extracellular matrix of hamster eggs: Exogenous activation by streptokinase

• Published in: Molecular reproduction and development Vol. 61; no. 4; pp. 528 - 535
• Main Authors: Jiménez-Díaz, María, Roldán, Mariela, Miceli, Dora C.
• Format: Journal Article
• Language: English
• Published: New York Wiley Subscription Services, Inc., A Wiley Company 01.04.2002; Wiley-Liss
• Subjects: Animals; Biological and medical sciences; Cricetinae; Enzyme Activation; extracellular matrix; Female; Fluorescent Antibody Technique, Indirect; Fundamental and applied biological sciences. Psychology; hamster eggs; Mammalian female genital system; Mesocricetus - physiology; Morphology. Physiology; oocytes; Ovum - physiology; plasminogen; Plasminogen - physiology; streptokinase; Streptokinase - physiology; Vertebrates: reproduction; Zona Pellucida - physiology; Rodentia; Activation; Germinal cell; Zona pellucida; Ovary; Vertebrata; Mammalia; Streptokinase; Female genital system; Female; Extracellular matrix; Plasminogen; Oocyte; Hamster
• ISSN: 1040-452X; 1098-2795
• DOI: 10.1002/mrd.10038

The plasminogen activator (PA)/plasminogen/plasmin proteolytic system has begun to be taken into account in the fertilization process. In this study, we demonstrated the presence of plasminogen in the extracellular matrix (ECM) of hamster oocytes by indirect immunofluorescence and immunoperoxidase assays using human anti‐plasminogen. Plasminogen appeared first on the zona pellucida (ZP) of ovarian oocytes and later on the plasma membrane (PM) of oviducal eggs. This would suggest that oviducal oocytes modulate the expression of plasminogen binding sites on the PM. Human plasminogen as well as that of other species, known to be activated by streptokinase (SK), is rapidly converted to a plasmin‐SK complex. We demonstrated the rapid formation of a SK‐plasminogen complex that yields plasmin in the blood plasma of hamsters. Both the in vivo and in vitro SK treatment of eggs from superovulated female hamsters caused a decreased in the ZP dissolution time (ZPdt), probably either due to the proteolytic effect of plasmin or due to the SK‐Plasminogen. Extracellular proteolysis assays carried out on agar–casein plates confirmed the proteolytic activity of SK‐incubated eggs; the controls, on the contrary, failed to display a halo. These studies show that (1) superovulated hamster eggs contain plasminogen in their ECM, (2) oviducal eggs exhibit plasminogen on their PMs, indicating the presence of their corresponding binding sites, (3) in hamsters, SK, a non‐enzymatic exogenous protein would be capable of activating ECM plasminogen to plasmin, and (4) the complex SK‐plasminogen and/or the plasmin are capable of changing the ZPdt with α‐chymotrypsin. Mol. Reprod. Dev. 61:528–535, 2002. © 2002 Wiley‐Liss, Inc.