Dev Biol 2005 Jun 01;2821:126-37. doi: 10.1016/j.ydbio.2005.02.033.

A Fringe-modified Notch signal affects specification of mesoderm and endoderm in the sea urchin embryo.

Abstract
Fringe proteins are O-fucose-specific beta-1,3 N-acetylglucosaminyltransferases that glycosylate the extracellular EGF repeats of Notch and enable Notch to be activated by the ligand Delta. In the sea urchin, signaling between Delta and Notch is known to be necessary for specification of secondary mesenchyme cells (SMCs). The Lytechinus variegatus Fringe homologue is expressed in both the signaling and receiving cells during this first Delta-Notch signal. Perturbation of Fringe expression through morpholino antisense oligonucleotide (MO) injection results in fewer SMCs but also causes decreased and delayed archenteron invagination. Partial endoderm specification occurs but expression of some endoderm genes is compromised. The data are consistent with a Fringe-requiring Notch signal as one upstream component of archenteron morphogenesis. Finally, Fringe perturbations result in more severe phenotypes than those previously reported for Notch dominant-negative (LvN(neg)) injections or reported here for Notch MO (NMO) injections. Injecting a combination of LvN(neg) and NMO results in a more severe phenotype than either treatment alone, and this combination phenocopies the fringe MO embryos. Taken together, the results show that Fringe is necessary both for maternal and zygotic Notch signals, and these Notch signals affect specification of mesoderm and endoderm.

PubMed ID: 15936334
Article link: Dev Biol
Grant support: [+]

Genes referenced: LOC100887844 LOC100889782 LOC105441151 LOC115921237 LOC115923437
Antibodies: msp130 Ab2
Morpholinos: LOC115923437 MO1