Functional studies of signaling pathways in peri-implantation development of the mouse embryo by RNAi.
BACKGROUND
Studies of gene function in the mouse have relied mainly on gene targeting via homologous recombination. However, this approach is difficult to apply in specific windows of time, and to simultaneously knock-down multiple genes. Here we report an efficient method for dsRNA-mediated gene silencing in late cleavage-stage mouse embryos that permits examination of phenotypes at post-implantation stages.


RESULTS
We show that introduction of Bmp4 dsRNA into intact blastocysts by electroporation recapitulates the genetic Bmp4 null phenotype at gastrulation. It also reveals a novel role for Bmp4 in the regulation the anterior visceral endoderm specific gene expression and its positioning. We also show that RNAi can be used to simultaneously target several genes. When applied to the three murine isoforms of Dishevelled, it leads to earlier defects than previously observed in double knock-outs. These include severe delays in post-implantation development and defects in the anterior midline and neural folds at headfold stages.


CONCLUSIONS
Our results indicate that the BMP4 signalling pathway contributes to the development of the anterior visceral endoderm, and reveal an early functional redundancy between the products of the murine Dishevelled genes. The proposed approach constitutes a powerful tool to screen the functions of genes that govern the development of the mouse embryo.
Soares
Miguel L
ML
The Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QR, UK. ms526@mole.bio.cam.ac.uk
Haraguchi
Seiki
S
Torres-Padilla
Maria-Elena
ME
Kalmar
Tibor
T
Carpenter
Lee
L
Bell
Graham
G
Morrison
Alastair
A
Ring
Christopher J A
CJ
Clarke
Neil J
NJ
Glover
David M
DM
Zernicka-Goetz
Magdalena
M
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001755:Blastocyst; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000502:physiology; D000072261:Dishevelled Proteins; D018274:Electroporation; D010064:Embryo Implantation / Q000502:physiology*; D047108:Embryonic Development; D004707:Endoderm; D020868:Gene Silencing; D008722:Methods; D051379:Mice; D010641:Phenotype; D010750:Phosphoproteins / Q000235:genetics / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology*; D015398:Signal Transduction / Q000502:physiology*
D048868:Adaptor Proteins, Signal Transducing; C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D000072261:Dishevelled Proteins; D010750:Phosphoproteins; D034741:RNA, Small Interfering