Megf8 (multiple EGF-like-domains 8) is widely expressed during early embryonic development with strong expression in the somites, limb buds, primordial gut, developing eye, and pharyngeal arches. Throughout embryogenesis and into the postnatal period, MEGF8 is present in the sensory neurons of the dorsal root ganglion and trigeminal ganglion, as well as the central nervous system including the developing neuroepithelium, postnatal hippocampus, layer 4/5 of the cortex and the olfactory bulb. Megf8 has been identified as a novel modifier of BMP4 (bone morphogenetic protein 4) signaling in trigeminal ganglion (TG) neurons. TG axon growth is robustly inhibited by
BMP4, and this inhibition is dependent on MEGF8 expression.
The last exon of Megf8 is flanked by loxP sites in this conditional mutant strain. Cre excision of the floxed region creates a knockout of the gene. Loss of MEGF8 disrupts axon guidance in the peripheral nervous system and leads to defects in development of the limb, heart, and left-right patterning, defects that resemble those observed in BMP4 loss-of-function mice.
