Expression of all Wnt genes and their secreted antagonists during mouse blastocyst and postimplantation development.
In this extensive study, real-time reverse transcriptase-polymerase chain reaction was used to analyze the expression levels of all 19 Wnt genes and their 11 potential antagonists in mouse blastocysts, pregastrula, gastrula, and neurula stages. By complementing these results with in situ hybridization, we revealed new expression domains for Wnt2b and Sfrp1, respectively, in the future primitive streak at the posterior side and in the anterior visceral endoderm before the initiation of gastrulation. Moreover, the anterior visceral endoderm expresses three secreted Wnt antagonists (Sfrp1, Sfrp5, and Dkk1) in partially overlapping domains. We also identified expression patterns for the Wnt1, Wnt3a, Wnt6, Wnt7b, Wnt9a, Wnt10b, and Sfrp1 genes at the blastocyst stage. In particular, the expression of Wnt1 and Sfrp1 predominantly in the inner cell mass and of Wnt9a in the mural trophoblast and inner cell mass cells surrounding the blastocoele suggests new roles for the Wnt pathway in preimplantation development. This article is the first report on the regional expression of Wnt genes in the mouse blastocyst.
Kemp
Caroline
C
Vrije Universiteit Brussel, Lab for Cell Genetics, Brussels, Belgium.
Willems
Erik
E
Abdo
Shaaban
S
Lambiv
Louis
L
Leyns
Luc
L
D000818:Animals; D001755:Blastocyst / Q000378:metabolism*; D010064:Embryo Implantation / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D015398:Signal Transduction; D051153:Wnt Proteins; D051155:Wnt1 Protein
D004791:Enzyme Inhibitors; D036341:Intercellular Signaling Peptides and Proteins; D051153:Wnt Proteins; D051155:Wnt1 Protein; C495246:Wnt1 protein, mouse