cki-1::GFP expression is visible in fed and starved L1s. Authors refer to aspects of the
cki-1::GFP.0 expression pattern that are common to fed and starved worms as developmentally regulated because they are seen during normal development in the presence of food and correlate with developmental regulation of cell division. In contrast, additional physiologically regulated expression is visible in the V lineage cells of starved but not fed L1s.In starved
daf-16(mgDf50) L1s, physiologically regulated
cki-1::GFP expression is absent or diminished in V lineage seam cells whereas developmentally regulated expression is undisturbed, indicating that DAF-16 is required for physiologically regulated expression of
cki-1::GFP. Because the
cki-1::GFP reporter contains genomic regulatory sequence but no
cki-1 coding sequence, this result suggests that during starvation, DAF-16 activates
cki-1 transcription in cells that would otherwise divide, or else DAF-16 function leads to the activation of
cki-1 transcription.