COORDINATE EXPRESSION OF SPLICE VARIANTS OF THE MURINE PREGNANCY-SPECIFIC GLYCOPROTEIN (PSG) GENE FAMILY DURING PLACENTAL DEVELOPMENT

Citation
B. Kromer et al., COORDINATE EXPRESSION OF SPLICE VARIANTS OF THE MURINE PREGNANCY-SPECIFIC GLYCOPROTEIN (PSG) GENE FAMILY DURING PLACENTAL DEVELOPMENT, European journal of biochemistry, 242(2), 1996, pp. 280-287
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology
Journal title
ISSN journal
0014-2956
Volume
242
Issue
2
Year of publication
1996
Pages
280 - 287
Database
ISI
SICI code
0014-2956(1996)242:2<280:CEOSVO>2.0.ZU;2-O
Abstract
The human and murine pregnancy-specific glycoprotein (PSG) gene famili es encode a large number of closely related proteins which are abundan tly expressed in the fetal trophoblast and secreted into the maternal circulation. Although the presence of a well conserved tripeptide sequ ence His or Arg-Gly-Asp or Glu or Lys (H/RGD/E/K) similar to the RGD m otif found in extracellular matrix proteins hints towards a possible i nteraction with integrin-type receptors, the function of this group of proteins related to the carcinoembryonic antigen family is still unkn own. It is also not clear whether the various members of the PSG famil y exert the same function. Here we describe the cloning of two splice variants of Cea4 (Cea4a, Cea4b), a murine PSG family member, which lac ks the RGD-related consensus motif. Cea4a, like most of the other rode nt PSG members, is composed of three immunoglobulin (Ig) variable-like domains (N1-N3) and and one Ig constant-like domain (A). In contrast, Cea4b lacks the N2 domain (N1N3A), demonstrating for the first time t hat PSG isoforms produced by alternative splicing also exist in mice. The mRNAs coding for Cea4a and Cea4b exhibit the same expression kinet ics during placental development as found for two other murine PSGs, C ea2 and Cea3, which contain the RGD-like motif. Expression starts afte r day 12.5 of embryonic development (E12.5) and maximum steady-state l evels are reached around E15.5-E17.5 as determined by RNase protection analyses. At E17.5, PSG transcripts can be detected exclusively in th e spongiotrophoblast of the placenta. In addition, PCR analyses reveal ed that Cea2, Cea3, and Cea4 transcripts are also found in RNA from a pool of embryos (E12-E15) but are absent from a number of adult tissue s tested (kidney, lung, testis, ovary, liver, brain, thymus, heart, sp leen). These results indicate that the various PSG isoforms exert thei r function(s) at the same time during placental and embryonic developm ent.