1st EXPERIMENTAL APPROACHES FROM THE PAPER THAT SUPPORTS A ROLE FOR RTK signaling IN THIS DEVELOPMENTAL EVENT:
In Verheyden et al. paper, one test involves looking at Fgf8 repression, to see if it represses Fgf4 VIA Germ1 INHIBITION. To do this they sought to block expression using a null allele for Grem1, and inserting it into a Fgf8-KO. With this system, no skeletal limbs were observed. And although AER was present, Fgf4 expression was not maintained. This showed Fgf8 repression of Fgf4 is DEPENDENT on Grem1.