PURIFICATION AND MOLECULAR-CLONING OF BOVINE OVIDUCT-SPECIFIC GLYCOPROTEIN

A specific 85-97-kDa (95-kDa) glycoprotein was found in bovine oviduct al tissue and fluid during the follicular phase. In this study, a 95-k Da bovine oviductal glycoprotein (95-kDa BOGP) was purified by wheat g erm agglutinin affinity and Mono-Q ion-exchange column chromatography. The first 29 NH2-terminal amino acid residues were determined by gas- phase microsequencing. A cDNA expression library prepared from poly(A) + RNA isolated from bovine oviducts was screened with a monoclonal ant ibody to 95-kDa BOGP. A single positive clone containing a approximate ly 2-kb cDNA insert was isolated. The coding region contained 1612 bp translating to 537 amino acids. The derived amino acid sequence contai ned a partial signal sequence of 18 amino acids followed by 29 amino a cids that were identical to the NH2-terminal amino acids determined by protein sequencing of purified 95-kDa BOGP. The amino acid sequence p redicted a mature protein of 519 amino acids (57 684 daltons) containi ng one potential N-linked glycosylation site and five cysteines. North ern blot hybridization with a digoxigenin-labeled probe indicated that a single message of approximately 2.5 kb was present in oviductal RNA , and this message was detected in significantly greater amounts in ov iductal RNA during the follicular phase than during the luteal phase. The amino acid sequence of a portion of 95-kDa BOGP was highly homolog ous (71% identity) to that of a baboon oviduct-specific glycoprotein.