Submission Number: ZHI-4-17-6

Abstract Number: 522

IDENTIFICATION OF A NOVEL KUNITZ-TYPE PROTEINASE INHIBITOR EXPRESSED BY EARLY PORCINE EMBRYOS.

Zhixin Wei, Jonathan A Green*, Lalantha Abeydeera*, Bill N Day*, R Michael Roberts* and Randall S Prather*

Department of Animal Science, University of Missouri, Columbia, MO ¹

Abstract:
Trophoblast investigation has been associated with the production of proteinases. The pig has a diffuse epitheliochorial placenta, in which the uterine surface epithelium remains intact with no invasion by the trophoblast. Proteinase inhibitors might play a role in regulating the degree of invasion. The porcine uterus synthesizes plasmin/trypsin inhibitor (UPTI), a member of the Kunitz family of proteinase inhibitors, which was first cloned by Stallings-Mann et al in 1994. In 1997 Duffy et al found the same mRNA was also produced by the developing trophoblast by day 15 of pregnancy and was present in the placenta throughout gestation. Here we describe a novel member of the Kunitz family of proteinase inhibitors expressed by in vivo and in vitro (IVF) derived early porcine embryos (2-cell, compact morula, and blastocyst stages). Embryos at different development stages were collected either from porcine oviduct or uterine flushing, or from IVM-IVF. They were analyzed by RT-PCR followed by subcloning and sequence analysis. A pair of PCR primers was designed based upon known UPTI sequences. Six clones (423bp) with identical sequences were obtained from these stages of embryo development. This new embryonic member of the Kunitz family, embryonic plasmin/trypsin inhibitor (EPTI) shares approximately 80% identity with the previously identified UPTI. EPTI's P1 residue, residue responsible for much of the proteinase inhibitory specificity in the Kunitz proteins, has the same amino acid (arginine) as does UPTI. This residue is different from the lysine at the P1 residue in bovine pancreatic trysin inhibitor (BPTI). The complete cDNA sequence of EPTI is under investigation. Its biological potential as a development marker, and its expression pattern during early embryonic/fetal development is the focus of our current work. (Funded in part by NIH, HD 34588) .

Keywords: Proteinase inhibitors, embryo development

This abstract is being presented at: 8:00 AM in session:
Implantation and Early Development