Probable transcription factor that is required for cell differentiation (PubMed:14527717, PubMed:24915236). Essential for proper separation of the sister chromatids during early nuclear division cycles in the syncytial pre-blastoderm embryo (PubMed:24915236). Expressed in embryos. RNAi-mediated knockdown in embryos is semi-lethal, with half of the mutants dying prior to gastrulation and display numerous vacuoles. Escaper embryos die at the third instar larval or early pupal stages, displaying black necrotic plaques. Named 'luna' based upon mutant embryo phenotype in which large vacuoles formed in the egg yolk resemble the lunar surface. Belongs to the krueppel C2H2-type zinc-finger protein family.