Project Summary for The MBRS Program, CSUN

Dr. Edward J. Carroll, Jr.
(818) 677-2004

Long term objectives:

To determine which of the isolated glycoproteins of the jelly coat may be significant in fertilization.  Another goal is to isolate and  identify the major glycoproteins of the vitelline envelope homologous to mammalian ZPA, ZPB and ZPC (also know as ZP1, ZP2 and ZP3).

Background:

The sperm of most vertebrates and invertebrates are surrounded by a primary egg envelope (the zone pellucida in mammals and vitelline envelope in amphibians and echinoderms, among others).  We now understand a great deal about the major glycoproteins in the envelope and their function in gamete interactions, to the extent that inhibitors of the functions of these molecules are being tested as contraceptives in humans.  Less is understood, however, about the coats that surround the primary envelopes (the cumulus layer in mammals and jelly coats in many other model systems).  Our laboratory uses the anuran, Lepidobatrachus laevis, a newer amphibian model system, to study mechanics of fertilization.  One goal is to isolate and purify the glycoproteins of the jelly coat.  Using this information we will determine which of the glycoproteins may be significant in fertilization.  Another is to isolate and identify the major glycoproteins of the vitelline envelope homologous to mammalian ZPA, ZPB and ZPC (also know as ZP1, ZP2 and ZP3).  ZPC has already been identified in Lepidobatrachus and the primary sequence determined in this laboratory.  Additionally, other processes involved in fertilization are less well understood, particularly mechanisms of final binding of sperm to receptors on the egg itself and the characterization, both cellular and molecular, of proteins and glycoproteins involved.  We are also studying the sperm of this species.  It has several unique features; it contains a double axoneme and an unusual accessory cell which is thought to be significant in the sperm's motility dynamics during fertilization.

Importance:

We use many different laboratory methods for all these studies including chemical separation and purification, molecular techniques and several forms of image analysis (EM, confocal, video and immunostaining).  The expertise required to perform these analyses is quite broad, ranging from the simplest fertility assays to test the isolated glycoproteins and observe their effects using basic light microscopy to the actual isolation, purification and identification of the glycoproteins (on both the cellular and molecular levels) and view their location and distribution using more complex microscopy techniques.

Experimental Methods:

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Report Writing:

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