OSM-11 Facilitates LIN-12 Notch Signaling during Caenorhabditis elegans Vulval Development (original) (raw)
Figure 2
osm-11 Encodes a Protein with a Conserved Motif Found in Notch Ligands
(A) Top: OSM-11 genomic structure. The signal peptide is shaded black, and putative O-linked glycosylation sites are indicated by vertical lines. The DOS motif is shaded blue; it overlaps the previously defined osmotic stress resistant (OSR) motif [52]. osm-11(rt142) removes all coding sequence after the signal peptide; osm-11(rt68) converts W177 to a premature stop codon. Bottom: the DOS motif-containing sequences from C. elegans OSM-11, OSM-7, DOS-1, DOS-2, and DOS-3 are aligned above the DOS motif consensus and the cEGF-1 consensus [53]. DOS-motif regions from mouse proteins and known Drosophila Notch ligands are aligned under the cEGF-1 consensus. DOS-motif amino acids are shaded blue and previously described EGF repeats are boxed. Asterisks (*) indicate cysteines in the conserved EGF-motif that are not found in the C. elegans DOS proteins. The DOS motif consensus is: C-X(3)-C-X(3,8)-C-X(2,5)-C-[KVER]-C-X(10,12)-C-X(1,3)-P-X(6,9)-C-X(1,4)-W-X(1,4)-C. In the DOS motif consensus, b represents K, V, E, or R, and the dash (-) indicates possible positions for proline in the DOS motif. In the cEGF-1 consensus, s represents a small amino acid [53].
(B) The position of the DOS motif in known or predicted C. elegans, Drosophila, and vertebrate Notch ligands. The DOS motif overlaps with the first two EGF repeats of canonical Notch ligands and may define a unique subset of EGF repeats. The noncanonical Notch ligands DNER [40], F3/contactin [95], and MAGP [36–40] do not contain a DOS motif (unpublished data).
(C) Similarity between DOS motifs, the first and second EGF repeats, and the third and fourth EGF repeats of Notch ligands. As noted by Lissemore and Starmer [27], the first and second EGF repeats differ from the third and fourth EGF repeats. DOS-3 was not included in this alignment. Green indicates the DOS motif of proteins that lack canonical EGF repeats; blue indicates the first and second EGF repeats of Notch ligands; red indicates the third and fourth EGF repeats of Notch ligands; and magenta represents the C. elegans Notch ligands that lack DSL domains. See Materials and Methods for accession numbers and other details.