370 amino acid Rel-homology region (RHR) is fused to lacZ coding region. Expression is driven by an Hsp83 promoter fragment. SV40 poly(A) signal is used for polyadenylation.
Maternal expression has no effects on the embryos. Zygotic expression causes lethality, lethality occurs at lethal or pupal stages. Lethal phenotype is accompanied by formation of melanotic tumours.