Premium
A developmentally regulated α2,8‐polysialyltransferase in embryos of the sea urchin Lytechinus pictus
Author(s) -
Cho Jin Won,
Troy Frederic A.,
Inoue Sadako,
Inoue Yasuo,
Lennarz William J.
Publication year - 1996
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.1996.t01-4-00004.x
Subject(s) - blastula , sea urchin , lytechinus variegatus , gastrulation , biology , microbiology and biotechnology , glycoprotein , embryo , biochemistry , spicule , chemistry , embryogenesis , anatomy , sponge spicule
The recent chemical identification of polysialylated glycoproteins in the jelly coat and on the cell surface of the sea urchin egg raises important questions about their biosynthesis and possible function. Using CMP‐[ 14 C]‐Neu5Ac as substrate and cell free preparations from eggs and embryos of the sea urchin Lytechinus pictus , we have identified a membrane associated CMP‐Neu5Ac:poly‐α2,8 sialosyl sialyltransferase (polyST) that transferred Neu5Ac from CMP‐Neu5Ac to an endogenous acceptor membrane protein of approximately 38kDa. An average of five to six [ 14 C]‐Neu5Ac residues were transferred to the glycan moiety of this protein. The membrane‐associated polyST also catalyzed the polysialylation of several exogenous mammalian ganglioside acceptors, including G D3 . Given that no structurally similar naturally occurring polysialylated gangliosides have been described, nor were observed in the present study, we conclude that a single polyST activity catalyzes sialylation of the endogenous acceptor protein and the gangliosides. Using an excess of G D3 as an exogenous acceptor, it was established that the expression of the polyST in L. pictus embryos increased rapidly at the mesenchyme blastula stage and reached a maximum at the gastrula stage. The finding that this polyST in the sea urchin embryo is developmentally regulated raises the possibility that it may play a role in the changing cell and tissue interactions that occur during gastrulation and the early stages of spicule formation.