Which of the following correctly describes the effect of glp-1 mutation in C. elegans embryos?
GLP-1 encodes C. elegans Notch receptor essential for AB lineage distinction. After first cleavage, P2 Delta signals via APX-1/LAG-2 activate GLP-1 only in ABp because ABa contact with P2 is minimal. This induces ABp-specific gene expression, including repression of LAG-2 in ABa. In glp-1 loss-of-function embryos, Notch signaling absent in ABp, so ABp defaults to ABa program, producing two ABa-like lineages with duplicated anterior pharynx cells and loss of dorsal ventral patterning. EMS division unaffected but overall embryo fails pharyngeal asymmetry. Thus transformation is ABp to ABa, class
Ref: Priess 2005; Gilbert, Developmental Biology 12th ed., Chapter 4: glp-1 mutation - ABp transforms into ABa.
