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The porcine trophoblastic interferon‐γ, secreted by a polarized epithelium, has specific structural and biochemical properties

The porcine trophoblastic interferon‐γ, secreted by a polarized epithelium, has specific... At the time of implantation in the maternal uterus, the trophectoderm of the pig blastocyst is the source of a massive secretion of interferon‐gamma (IFN‐γ), together with lesser amounts of IFN‐δ, a unique species of type I IFN. This trophoblastic IFN‐γ (TrIFN‐γ) is an unprecedented example of IFN‐γ being produced spontaneously by an epithelium. We therefore studied some of its structural and biochemical properties, by comparison with pig IFN‐γ from other sources, either natural LeIFN‐γ (from adult leucocytes), or recombinant. Biologically active TrIFN‐γ is a dimeric molecule, of which monomers are mainly composed of a truncated polypeptide chain with two glycotypes, unlike LeIFN‐γ which is formed of at least two polypeptide chains and four glycotypes. TrIFN‐γ collected in the uterus lumen was enzymatically deglycosylated and analysed by mass spectrometry (MALDI‐TOF). The data revealed that the more abundant polypeptide has a mass of 14.74 kDa, corresponding to a C‐terminal cleavage of 17 residues from the expected 143‐residue long mature sequence. A minor polypeptide, with a mass of 12.63 kDa, corresponds to a C‐terminal truncation of 36 amino acids. MALDI‐TOF analysis of tryptic peptides from the glycosylated molecule(s) identifies a single branched carbohydrate motif, with six N‐acetylgalactosamines, and no sialic acid. The only glycan microheterogeneity seems to reside in the number of l‐fucose residues (one to three). The lack of the C‐terminal cluster of basic residues, and the presence of nonsialylated glycans, result in a very low net charge of TrIFN‐γ molecule. However, the 17‐residue truncation does not affect the antiproliferative activity of TrIFN‐γ on different cells, among which is a porcine uterine epithelial cell line. It is suggested that these specific properties might confer on TrIFN‐γ a particular ability to invade the uterine mucosa and exert biological functions beyond the endometrial epithelium. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Febs Journal Wiley

The porcine trophoblastic interferon‐γ, secreted by a polarized epithelium, has specific structural and biochemical properties

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References (35)

Publisher
Wiley
Copyright
Copyright © 2002 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1742-464X
eISSN
1742-4658
DOI
10.1046/j.1432-1033.2002.02950.x
Publisher site
See Article on Publisher Site

Abstract

At the time of implantation in the maternal uterus, the trophectoderm of the pig blastocyst is the source of a massive secretion of interferon‐gamma (IFN‐γ), together with lesser amounts of IFN‐δ, a unique species of type I IFN. This trophoblastic IFN‐γ (TrIFN‐γ) is an unprecedented example of IFN‐γ being produced spontaneously by an epithelium. We therefore studied some of its structural and biochemical properties, by comparison with pig IFN‐γ from other sources, either natural LeIFN‐γ (from adult leucocytes), or recombinant. Biologically active TrIFN‐γ is a dimeric molecule, of which monomers are mainly composed of a truncated polypeptide chain with two glycotypes, unlike LeIFN‐γ which is formed of at least two polypeptide chains and four glycotypes. TrIFN‐γ collected in the uterus lumen was enzymatically deglycosylated and analysed by mass spectrometry (MALDI‐TOF). The data revealed that the more abundant polypeptide has a mass of 14.74 kDa, corresponding to a C‐terminal cleavage of 17 residues from the expected 143‐residue long mature sequence. A minor polypeptide, with a mass of 12.63 kDa, corresponds to a C‐terminal truncation of 36 amino acids. MALDI‐TOF analysis of tryptic peptides from the glycosylated molecule(s) identifies a single branched carbohydrate motif, with six N‐acetylgalactosamines, and no sialic acid. The only glycan microheterogeneity seems to reside in the number of l‐fucose residues (one to three). The lack of the C‐terminal cluster of basic residues, and the presence of nonsialylated glycans, result in a very low net charge of TrIFN‐γ molecule. However, the 17‐residue truncation does not affect the antiproliferative activity of TrIFN‐γ on different cells, among which is a porcine uterine epithelial cell line. It is suggested that these specific properties might confer on TrIFN‐γ a particular ability to invade the uterine mucosa and exert biological functions beyond the endometrial epithelium.

Journal

The Febs JournalWiley

Published: Jan 1, 2002

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