Progressive tarsal patterning in the Drosophila by temporally dynamic regulation of transcription factor genes

► We investigate the gene interaction during the tarsal patterning. ► nubbin prevents rotund from being activated by tarsal-less and spineless. ► Gradual nubbin disappearance causes gradual Bar repression through rn derepression. ► Initiation of apterous expression makes Bar refractory to rotund. ► Timely interaction of these genes creates the middle tarsal segments.