In , broad complex, tramtrack, bric A brac (BTB)/poxvirus and zinc finger (POZ) transcription factors are essential regulators of development. We searched the genome for BTB/POZ-ZF domains and discovered an unknown gene, , which encodes an orthologue of human . We then characterized the biological function of the via genetic interaction analysis. Ectopic expression of in the wing induced extra vein formation during wing development in . Genetic interactions between and Ras or extracellular signal-regulated kinase (ERK) significantly enhanced the formation of vein cells. On the other hand, loss-of-function mutations in resulted in a dramatic suppression of the extra and ectopic vein formation induced by elevated Ras/ERK signaling. Moreover, activity upregulated the expression of and , which perform crucial functions in vein cell formation in the developing wing. These results indicate that dPLZF is a transcription factor controlled by the Ras/ERK signaling pathway, which is a prominent regulator of vein cell formation during wing development in .