Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Cells Tissues Organs 2007;185:269–284 DOI: 10.1159/000102175 Glycosylation at the Fetomaternal Interface in Hemomonochorial Placentae from Five Widely Separated Species of Mammal: Is There Evidence for Convergent Evolution? Carolyn J.P. Jones a Anthony M. Carter b John D. Aplin a Allen C. Enders c a Division of Human Development, University of Manchester, St. Mary’s Hospital, Manchester , UK; b Department of Physiology and Pharmacology, University of Southern Denmark, Odense, Denmark; c Department of Cell Biology and Human Anatomy, University of California School of Medicine, Davis, Calif., USA all five species showed marked similarities in glycosylation. In the N-linked series, there were abundant bi/tri-antennary complex chains, while the non-bisected variants were much scarcer. All species had plentiful N-acetyl lactosamine se- quences; at chain termini, binding to Gal 1,4GlcNAc and Gal 1,3GalNAc sequences was greatly enhanced after neur- aminidase treatment. In all species, terminal NeuNAc 2,3 residues were detected. The tenrec had unusually abundant terminal N-acetyl galactosamine. The basal plasma mem- brane/basal lamina showed glycosylation patterns distinct from the microvillous membrane in each case, indicating chemical diversity of the two opposite faces of trophoblast. Similar classes of glycan at the hemochorial interface sug- gest conservation of function. The observed lectin binding patterns suggest broad similarities of glycosylation that may have arisen by convergent evolution. Copyright © 2007 S. Karger AG, Basel Introduction Hemochorial placentation occurs in species as diverse as primates, rodents, insectivores and bats [Carter 2001; Enders and Carter, 2004]. This paper investigates to what extent expression of glycans on the maternal-facing tro- phoblast differs between hemochorial placentae from Key Words Evolution  Glycan  Hemomonochorial placenta  Lectin  Surface membrane Abstract Hemomonochorial placentation occurs in diverse species. We have examined placental glycosylation in five widely separated mammals with this type of placentation – lesser hedgehog tenrec (Echinops telfairi) , spotted hyena (Crocuta crocuta) , nine-banded armadillo (Dasypus novemcinctus) , human (Homo sapiens) and guinea pig (Cavia porcellus) – in order to assess whether evolutionary convergence to the he- momonochorial state is accompanied by a similar conver- gence of glycan expression. Placentae from 2 E. telfairi, 3 C. crocuta, 1 D. novemcinctus , 4 women and 1 C. porcellus were fixed and processed into epoxy resin. Binding of twenty- three lectins was assessed using a semiquantitative ranking system. The trophoblast apical/microvillous membrane of Accepted after revision: January 17, 2007 Dr. Carolyn J.P. Jones Research Floor, Department of Obstetrics and Gynecology St. Mary’s Hospital, Hathersage Road Manchester M13 0JH (UK) Tel. +44 161 276 6435, Fax +44 161 224 1013, E-Mail carolyn.jones@manchester.ac.uk © 2007 S. Karger AG, Basel 1422–6405/07/1854–0269$23.50/0 Accessible online at: www.karger.com/cto Abbreviations used in this paper Phosphate-buffered saline Tris-buffered saline PBS TBS